diff --git a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
index 9a05bbf6956..476c2860f12 100644
--- a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
+++ b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.js
@@ -93,13 +93,13 @@ export class AttachmentViewer extends Component {
      * @private
      */
     _handleImageLoad() {
-        if (!this.attachmentViewer.exists() || !this.attachmentViewer.attachment) {
+        if (!this.attachmentViewer.exists() || !this.attachmentViewer.attachmentViewerViewable) {
             return;
         }
         const refs = this._getRefs();
-        const image = refs[`image_${this.attachmentViewer.attachment.id}`];
+        const image = refs[`image_${this.attachmentViewer.attachmentViewerViewable.localId}`];
         if (
-            this.attachmentViewer.attachment.isImage &&
+            this.attachmentViewer.attachmentViewerViewable.isImage &&
             (!image || !image.complete)
         ) {
             this.attachmentViewer.update({ isImageLoading: true });
@@ -142,7 +142,7 @@ export class AttachmentViewer extends Component {
     _updateZoomerStyle() {
         const attachmentViewer = this.attachmentViewer;
         const refs = this._getRefs();
-        const image = refs[`image_${this.attachmentViewer.attachment.id}`];
+        const image = refs[`image_${this.attachmentViewer.attachmentViewerViewable.localId}`];
         const tx = image.offsetWidth * attachmentViewer.scale > this._zoomerRef.el.offsetWidth
             ? this._translate.x + this._translate.dx
             : 0;
diff --git a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.xml b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.xml
index d92ff351df5..994f3dd9072 100644
--- a/addons/mail/static/src/components/attachment_viewer/attachment_viewer.xml
+++ b/addons/mail/static/src/components/attachment_viewer/attachment_viewer.xml
@@ -5,24 +5,24 @@
         <t t-if="attachmentViewer">
             <div class="o_AttachmentViewer flex-column align-items-center d-flex w-100 h-100" t-attf-class="{{ className }}" t-on-click="attachmentViewer.onClick" t-on-keydown="_onKeydown" tabindex="0" t-ref="root">
                 <div class="o_AttachmentViewer_header d-flex w-100 bg-black-75 text-400" t-on-click="attachmentViewer.onClickHeader">
-                    <t t-if="attachmentViewer.attachment.isViewable">
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isViewable">
                         <div class="o_AttachmentViewer_headerItem o_AttachmentViewer_icon d-flex align-items-center ms-4 me-2">
-                            <t t-if="attachmentViewer.attachment.isImage">
+                            <t t-if="attachmentViewer.attachmentViewerViewable.isImage">
                                 <i class="fa fa-picture-o" role="img" title="Image"/>
                             </t>
-                            <t t-if="attachmentViewer.attachment.isPdf">
+                            <t t-if="attachmentViewer.attachmentViewerViewable.isPdf">
                                 <i class="fa fa-file-text" role="img" title="PDF file"/>
                             </t>
-                            <t t-if="attachmentViewer.attachment.isText">
+                            <t t-if="attachmentViewer.attachmentViewerViewable.isText">
                                 <i class="fa fa-file-text" role="img" title="Text file"/>
                             </t>
-                            <t t-if="attachmentViewer.attachment.isVideo">
+                            <t t-if="attachmentViewer.attachmentViewerViewable.isVideo">
                                 <i class="fa fa-video-camera" role="img" title="Video"/>
                             </t>
                         </div>
                     </t>
                     <div class="o_AttachmentViewer_headerItem o_AttachmentViewer_name d-flex align-items-center mx-2">
-                        <span class="o_AttachmentViewer_nameText text-truncate" t-esc="attachmentViewer.attachment.displayName"/>
+                        <span class="o_AttachmentViewer_nameText text-truncate" t-esc="attachmentViewer.attachmentViewerViewable.displayName"/>
                     </div>
                     <div class="flex-grow-1"/>
                     <div class="o_AttachmentViewer_buttonDownload o_AttachmentViewer_headerItem o_AttachmentViewer_headerItemButton d-flex align-items-center px-3 o_cursor_pointer" t-on-click="attachmentViewer.onClickDownload" role="button" title="Download">
@@ -35,33 +35,33 @@
                         <i class="fa fa-fw fa-times" role="img"/>
                     </div>
                 </div>
-                <div class="o_AttachmentViewer_main position-absolute top-0 bottom-0 start-0 end-0 align-items-center justify-content-center d-flex" t-att-class="{ 'o_with_img overflow-hidden': attachmentViewer.attachment.isImage }" t-on-mousemove="_onMousemoveView">
-                    <t t-if="attachmentViewer.attachment.isImage">
+                <div class="o_AttachmentViewer_main position-absolute top-0 bottom-0 start-0 end-0 align-items-center justify-content-center d-flex" t-att-class="{ 'o_with_img overflow-hidden': attachmentViewer.attachmentViewerViewable.isImage }" t-on-mousemove="_onMousemoveView">
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isImage">
                         <div class="o_AttachmentViewer_zoomer position-absolute align-items-center justify-content-center d-flex w-100 h-100" t-ref="zoomer">
                             <t t-if="attachmentViewer.isImageLoading">
                                 <div class="o_AttachmentViewer_loading position-absolute">
                                     <i class="fa fa-3x fa-circle-o-notch fa-fw fa-spin text-white" role="img" title="Loading"/>
                                 </div>
                             </t>
-                            <img class="o_AttachmentViewer_view o_AttachmentViewer_viewImage mw-100 mh-100 bg-black" t-on-click="attachmentViewer.onClickImage" t-on-mousedown="_onMousedownImage" t-on-wheel="_onWheelImage" t-on-load="attachmentViewer.onLoadImage" t-att-src="attachmentViewer.imageUrl" t-att-style="attachmentViewer.imageStyle" draggable="false" alt="Viewer" t-key="'image_' + attachmentViewer.attachment.id" t-ref="image_{{ attachmentViewer.attachment.id }}"/>
+                            <img class="o_AttachmentViewer_view o_AttachmentViewer_viewImage mw-100 mh-100 bg-black" t-on-click="attachmentViewer.onClickImage" t-on-mousedown="_onMousedownImage" t-on-wheel="_onWheelImage" t-on-load="attachmentViewer.onLoadImage" t-att-src="attachmentViewer.attachmentViewerViewable.imageUrl" t-att-style="attachmentViewer.imageStyle" draggable="false" alt="Viewer" t-key="'image_' + attachmentViewer.attachmentViewerViewable.localId" t-ref="image_{{ attachmentViewer.attachmentViewerViewable.localId }}"/>
                         </div>
                     </t>
-                    <t t-if="attachmentViewer.attachment.isPdf">
-                        <iframe class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_AttachmentViewer_viewPdf w-75 h-100 bg-black border-0" t-ref="iframeViewerPdf" t-att-class="{ 'w-100': messaging.device.isSmall }" t-att-src="attachmentViewer.attachment.defaultSource"/>
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isPdf">
+                        <iframe class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_AttachmentViewer_viewPdf w-75 h-100 bg-black border-0" t-ref="iframeViewerPdf" t-att-class="{ 'w-100': messaging.device.isSmall }" t-att-src="attachmentViewer.attachmentViewerViewable.defaultSource"/>
                     </t>
-                    <t t-if="attachmentViewer.attachment.isText">
-                        <iframe class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_text w-75 h-100 bg-white border-0" t-att-src="attachmentViewer.attachment.defaultSource"/>
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isText">
+                        <iframe class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_text w-75 h-100 bg-white border-0" t-att-src="attachmentViewer.attachmentViewerViewable.defaultSource"/>
                     </t>
-                    <t t-if="attachmentViewer.attachment.isUrlYoutube">
-                        <iframe allow="autoplay; encrypted-media" class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_AttachmentViewer_youtube w-75 h-100 bg-black border-0" t-att-src="attachmentViewer.attachment.defaultSource" height="315" width="560"/>
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isUrlYoutube">
+                        <iframe allow="autoplay; encrypted-media" class="o_AttachmentViewer_view o_AttachmentViewer_viewIframe o_AttachmentViewer_youtube w-75 h-100 bg-black border-0" t-att-src="attachmentViewer.attachmentViewerViewable.defaultSource" height="315" width="560"/>
                     </t>
-                    <t t-if="attachmentViewer.attachment.isVideo">
+                    <t t-if="attachmentViewer.attachmentViewerViewable.isVideo">
                         <video class="o_AttachmentViewer_view o_AttachmentViewer_viewVideo w-75 h-75 bg-black" t-att-class="{ 'w-100 h-100': messaging.device.isSmall }" t-on-click="attachmentViewer.onClickVideo" controls="controls">
-                            <source t-att-data-type="attachmentViewer.attachment.mimetype" t-att-src="attachmentViewer.attachment.defaultSource"/>
+                            <source t-att-data-type="attachmentViewer.attachmentViewerViewable.mimetype" t-att-src="attachmentViewer.attachmentViewerViewable.defaultSource"/>
                         </video>
                     </t>
                 </div>
-                <t t-if="attachmentViewer.attachment.isImage">
+                <t t-if="attachmentViewer.attachmentViewerViewable.isImage">
                     <div class="o_AttachmentViewer_toolbar position-absolute bottom-0 d-flex" role="toolbar">
                         <div class="o_AttachmentViewer_toolbarButton btn btn-dark p-3 rounded-0" t-on-click="_onClickZoomIn" title="Zoom In (+)" role="button">
                             <i class="fa fa-fw fa-plus" role="img"/>
@@ -83,7 +83,7 @@
                         </div>
                     </div>
                 </t>
-                <t t-if="attachmentViewer.attachments.length > 1">
+                <t t-if="attachmentViewer.attachmentViewerViewables.length > 1">
                     <div class="o_AttachmentViewer_buttonNavigation o_AttachmentViewer_buttonNavigationPrevious o_AttachmentViewer_buttonNavigationPreviousIcon btn btn-dark position-absolute top-0 bottom-0 start-0 align-items-center justify-content-center d-flex my-auto ms-3 rounded-circle" t-on-click="attachmentViewer.onClickPrevious" title="Previous (Left-Arrow)" role="button">
                         <span class="fa fa-chevron-left" role="img"/>
                     </div>
diff --git a/addons/mail/static/src/models/attachment.js b/addons/mail/static/src/models/attachment.js
index 4c2a9eddd26..9e0282f51cb 100644
--- a/addons/mail/static/src/models/attachment.js
+++ b/addons/mail/static/src/models/attachment.js
@@ -300,6 +300,10 @@ registerModel({
         attachmentLists: many('AttachmentList', {
             inverse: 'attachments',
         }),
+        attachmentViewerViewable: one('AttachmentViewerViewable', {
+            inverse: 'attachmentOwner',
+            isCausal: true,
+        }),
         checksum: attr(),
         /**
          * States on which composer this attachment is currently being created.
diff --git a/addons/mail/static/src/models/attachment_viewer.js b/addons/mail/static/src/models/attachment_viewer.js
index 9e6a38e4bff..2e24fd88769 100644
--- a/addons/mail/static/src/models/attachment_viewer.js
+++ b/addons/mail/static/src/models/attachment_viewer.js
@@ -2,6 +2,7 @@
 
 import { registerModel } from '@mail/model/model_core';
 import { attr, many, one } from '@mail/model/model_field';
+import { clear, insertAndReplace, replace } from '@mail/model/model_field_command';
 
 registerModel({
     name: 'AttachmentViewer',
@@ -59,7 +60,7 @@ registerModel({
          */
         onClickDownload(ev) {
             ev.stopPropagation();
-            this.attachment.download();
+            this.attachmentViewerViewable.download();
         },
         /**
          * Called when clicking on the header. Stop propagation of event to prevent
@@ -181,17 +182,27 @@ registerModel({
         },
         /**
          * @private
-         * @returns {string}
          */
-        _computeImageUrl() {
-            if (!this.attachment) {
-                return;
+        _computeAttachmentViewerViewable() {
+            if (this.attachmentList) {
+                return insertAndReplace({
+                    attachmentOwner: replace(this.attachmentList.selectedAttachment),
+                });
             }
-            if (!this.attachment.accessToken && this.attachment.originThread && this.attachment.originThread.model === 'mail.channel') {
-                return `/mail/channel/${this.attachment.originThread.id}/image/${this.attachment.id}`;
+            return clear();
+        },
+        /**
+         * @private
+         */
+        _computeAttachmentViewerViewables() {
+            if (this.attachmentList) {
+                return insertAndReplace(
+                    this.attachmentList.viewableAttachments.map((attachment) => {
+                        return { attachmentOwner: replace(attachment) };
+                    })
+                );
             }
-            const accessToken = this.attachment.accessToken ? `?access_token=${this.attachment.accessToken}` : '';
-            return `/web/image/${this.attachment.id}${accessToken}`;
+            return clear();
         },
         /**
          * @private
@@ -221,15 +232,14 @@ registerModel({
         angle: attr({
             default: 0,
         }),
-        attachment: one('Attachment', {
-            related: 'attachmentList.selectedAttachment',
-        }),
         attachmentList: one('AttachmentList', {
             related: 'dialogOwner.attachmentListOwnerAsAttachmentView',
-            required: true,
         }),
-        attachments: many('Attachment', {
-            related: 'attachmentList.viewableAttachments',
+        attachmentViewerViewable: one("AttachmentViewerViewable", {
+            compute: "_computeAttachmentViewerViewable",
+        }),
+        attachmentViewerViewables: many("AttachmentViewerViewable", {
+            compute: "_computeAttachmentViewerViewables",
         }),
         /**
          * States the OWL component of this attachment viewer.
@@ -249,13 +259,6 @@ registerModel({
         imageStyle: attr({
             compute: '_computeImageStyle',
         }),
-        /**
-         * Determines the source URL to use for the image.
-         */
-        imageUrl: attr({
-            compute: '_computeImageUrl',
-            readonly: true,
-        }),
         /**
          * Determine whether the user is currently dragging the image.
          * This is useful to determine whether a click outside of the image
diff --git a/addons/mail/static/src/models/attachment_viewer_viewable.js b/addons/mail/static/src/models/attachment_viewer_viewable.js
new file mode 100644
index 00000000000..1601fd9453e
--- /dev/null
+++ b/addons/mail/static/src/models/attachment_viewer_viewable.js
@@ -0,0 +1,134 @@
+/** @odoo-module **/
+
+import { registerModel } from "@mail/model/model_core";
+import { attr, one } from "@mail/model/model_field";
+
+/**
+ * Intermediary model to facilitate adding support for additional
+ * models to the AttachmentViewer.
+ */
+
+registerModel({
+    name: "AttachmentViewerViewable",
+    identifyingFields: [["attachmentOwner"]],
+    recordMethods: {
+        download() {
+            return this.attachmentOwner.download();
+        },
+        /**
+         * @private
+         */
+        _computeAccessToken() {
+            return this.attachmentOwner.accessToken;
+        },
+        /**
+         * @private
+         */
+        _computeDefaultSource() {
+            return this.attachmentOwner.defaultSource;
+        },
+        /**
+         * @private
+         */
+        _computeDisplayName() {
+            return this.attachmentOwner.displayName;
+        },
+        /**
+         * @private
+         */
+        _computeImageUrl() {
+            if (
+                !this.attachmentOwner.accessToken &&
+                this.attachmentOwner.originThread &&
+                this.attachmentOwner.originThread.model === "mail.channel"
+            ) {
+                return `/mail/channel/${this.attachmentOwner.originThread.id}/image/${this.attachmentOwner.id}`;
+            }
+            const accessToken = this.attachmentOwner.accessToken
+                ? `?access_token=${this.attachmentOwner.accessToken}`
+                : "";
+            return `/web/image/${this.attachmentOwner.id}${accessToken}`;
+        },
+        /**
+         * @private
+         */
+        _computeIsImage() {
+            return this.attachmentOwner.isImage;
+        },
+        /**
+         * @private
+         */
+        _computeIsPdf() {
+            return this.attachmentOwner.isPdf;
+        },
+        /**
+         * @private
+         */
+        _computeIsText() {
+            return this.attachmentOwner.isText;
+        },
+        /**
+         * @private
+         */
+        _computeIsUrlYoutube() {
+            return this.attachmentOwner.isUrlYoutube;
+        },
+        /**
+         * @private
+         */
+        _computeIsVideo() {
+            return this.attachmentOwner.isVideo;
+        },
+        /**
+         * @private
+         */
+        _computeIsViewable() {
+            return this.attachmentOwner.isViewable;
+        },
+        /**
+         * @private
+         */
+        _computeMimetype() {
+            return this.attachmentOwner.mimetype;
+        },
+    },
+    fields: {
+        attachmentOwner: one("Attachment", {
+            inverse: 'attachmentViewerViewable',
+            readonly: true,
+        }),
+        accessToken: attr({
+            compute: "_computeAccessToken",
+        }),
+        defaultSource: attr({
+            compute: "_computeDefaultSource",
+        }),
+        displayName: attr({
+            compute: "_computeDisplayName",
+        }),
+        imageUrl: attr({
+            compute: "_computeImageUrl",
+        }),
+        isImage: attr({
+            compute: "_computeIsImage",
+        }),
+        isPdf: attr({
+            compute: "_computeIsPdf",
+        }),
+        isText: attr({
+            compute: "_computeIsText",
+        }),
+        isUrlYoutube: attr({
+            compute: "_computeIsUrlYoutube",
+        }),
+        isVideo: attr({
+            compute: "_computeIsVideo",
+        }),
+        isViewable: attr({
+            compute: "_computeIsViewable",
+        }),
+        mimetype: attr({
+            compute: "_computeMimetype",
+        }),
+    },
+});