diff --git a/addons/hr/static/src/models/employee/employee.js b/addons/hr/static/src/models/employee/employee.js
index 0cf877baab6..6d3c12cb14b 100644
--- a/addons/hr/static/src/models/employee/employee.js
+++ b/addons/hr/static/src/models/employee/employee.js
@@ -36,7 +36,7 @@ function factory(dependencies) {
                     const userData = {
                         id: userNameGet[0],
                         partner: [['insert', partnerData]],
-                        partnerDisplayName: userNameGet[1],
+                        display_name: userNameGet[1],
                     };
                     data2.user = [['insert', userData]];
                 }
diff --git a/addons/mail/static/src/components/activity/activity.js b/addons/mail/static/src/components/activity/activity.js
index 45fb2d12a8e..633c43820d6 100644
--- a/addons/mail/static/src/components/activity/activity.js
+++ b/addons/mail/static/src/components/activity/activity.js
@@ -34,7 +34,7 @@ class Activity extends Component {
                 assigneeNameOrDisplayName: (
                     activity &&
                     activity.assignee &&
-                    activity.assignee.nameOrDisplayName()
+                    activity.assignee.nameOrDisplayName
                 ),
             };
         });
@@ -60,7 +60,7 @@ class Activity extends Component {
      * @returns {string}
      */
     get assignedUserText() {
-        return _.str.sprintf(this.env._t("for %s"), this.activity.assignee.nameOrDisplayName());
+        return _.str.sprintf(this.env._t("for %s"), this.activity.assignee.nameOrDisplayName);
     }
 
     /**
diff --git a/addons/mail/static/src/components/activity/activity.xml b/addons/mail/static/src/components/activity/activity.xml
index d8ae1808bf5..87b22dbca99 100644
--- a/addons/mail/static/src/components/activity/activity.xml
+++ b/addons/mail/static/src/components/activity/activity.xml
@@ -7,7 +7,7 @@
                 <div class="o_Activity_sidebar">
                     <div class="o_Activity_user">
                         <t t-if="activity.assignee">
-                            <img class="o_Activity_userAvatar" t-attf-src="/web/image/res.users/{{ activity.assignee.id }}/image_128" t-att-alt="activity.assignee.nameOrDisplayName()"/>
+                            <img class="o_Activity_userAvatar" t-attf-src="/web/image/res.users/{{ activity.assignee.id }}/image_128" t-att-alt="activity.assignee.nameOrDisplayName"/>
                         </t>
                         <div class="o_Activity_iconContainer"
                             t-att-class="{
@@ -65,17 +65,17 @@
                                     <dt>Created</dt>
                                     <dd class="o_Activity_detailsCreation">
                                         <t t-esc="formattedCreateDatetime"/>
-                                        <img class="o_Activity_detailsUserAvatar o_Activity_detailsCreatorAvatar" t-attf-src="/web/image/res.users/{{ activity.creator.id }}/image_128" t-att-title="activity.creator.nameOrDisplayName()" t-att-alt="activity.creator.nameOrDisplayName()"/>
+                                        <img class="o_Activity_detailsUserAvatar o_Activity_detailsCreatorAvatar" t-attf-src="/web/image/res.users/{{ activity.creator.id }}/image_128" t-att-title="activity.creator.nameOrDisplayName" t-att-alt="activity.creator.nameOrDisplayName"/>
                                         <span class="o_Activity_detailsCreator">
-                                            <t t-esc="activity.creator.nameOrDisplayName()"/>
+                                            <t t-esc="activity.creator.nameOrDisplayName"/>
                                         </span>
                                     </dd>
                                 </t>
                                 <t t-if="activity.assignee">
                                     <dt>Assigned to</dt>
                                     <dd class="o_Activity_detailsAssignation">
-                                        <img class="o_Activity_detailsUserAvatar o_Activity_detailsAssignationUserAvatar" t-attf-src="/web/image/res.users/{{ activity.assignee.id }}/image_128" t-att-title="activity.assignee.nameOrDisplayName()" t-att-alt="activity.assignee.nameOrDisplayName()"/>
-                                        <t t-esc="activity.assignee.nameOrDisplayName()"/>
+                                        <img class="o_Activity_detailsUserAvatar o_Activity_detailsAssignationUserAvatar" t-attf-src="/web/image/res.users/{{ activity.assignee.id }}/image_128" t-att-title="activity.assignee.nameOrDisplayName" t-att-alt="activity.assignee.nameOrDisplayName"/>
+                                        <t t-esc="activity.assignee.nameOrDisplayName"/>
                                     </dd>
                                 </t>
                                 <dt>Due on</dt>
diff --git a/addons/mail/static/src/components/activity/activity_tests.js b/addons/mail/static/src/components/activity/activity_tests.js
index dce0969159d..bea2a552a5f 100644
--- a/addons/mail/static/src/components/activity/activity_tests.js
+++ b/addons/mail/static/src/components/activity/activity_tests.js
@@ -375,7 +375,7 @@ QUnit.test('activity details toggle', async function (assert) {
     const tomorrow = new Date();
     tomorrow.setDate(today.getDate() + 1);
     const activity = this.env.models['mail.activity'].create({
-        creator: [['insert', { id: 1, partnerDisplayName: "Admin" }]],
+        creator: [['insert', { id: 1, display_name: "Admin" }]],
         dateCreate: date_to_str(today),
         dateDeadline: date_to_str(tomorrow),
         state: 'planned',
@@ -425,8 +425,8 @@ QUnit.test('activity details layout', async function (assert) {
     const tomorrow = new Date();
     tomorrow.setDate(today.getDate() + 1);
     const activity = this.env.models['mail.activity'].create({
-        assignee: [['insert', { id: 10, partnerDisplayName: "Pauvre pomme" }]],
-        creator: [['insert', { id: 1, partnerDisplayName: "Admin" }]],
+        assignee: [['insert', { id: 10, display_name: "Pauvre pomme" }]],
+        creator: [['insert', { id: 1, display_name: "Admin" }]],
         dateCreate: date_to_str(today),
         dateDeadline: date_to_str(tomorrow),
         state: 'planned',
diff --git a/addons/mail/static/src/models/activity/activity.js b/addons/mail/static/src/models/activity/activity.js
index 4e654e3c456..7b2cd9bc0eb 100644
--- a/addons/mail/static/src/models/activity/activity.js
+++ b/addons/mail/static/src/models/activity/activity.js
@@ -94,7 +94,7 @@ function factory(dependencies) {
                     data2.creator = [
                         ['insert', {
                             id: data.create_uid[0],
-                            partnerDisplayName: data.create_uid[1],
+                            display_name: data.create_uid[1],
                         }],
                     ];
                 }
@@ -109,7 +109,7 @@ function factory(dependencies) {
                     data2.assignee = [
                         ['insert', {
                             id: data.user_id[0],
-                            partnerDisplayName: data.user_id[1],
+                            display_name: data.user_id[1],
                         }],
                     ];
                 }
diff --git a/addons/mail/static/src/models/partner/partner.js b/addons/mail/static/src/models/partner/partner.js
index eb56720b862..4a8a1c54f0d 100644
--- a/addons/mail/static/src/models/partner/partner.js
+++ b/addons/mail/static/src/models/partner/partner.js
@@ -56,7 +56,7 @@ function factory(dependencies) {
                     data2.user = [
                         ['insert', {
                             id: data.user_id[0],
-                            partnerDisplayName: data.user_id[1],
+                            display_name: data.user_id[1],
                         }],
                     ];
                 }
@@ -246,7 +246,15 @@ function factory(dependencies) {
 
         /**
          * @private
-         * @returns {string}
+         * @returns {string|undefined}
+         */
+        _computeDisplayName() {
+            return this.display_name || this.user && this.user.display_name;
+        }
+
+        /**
+         * @private
+         * @returns {string|undefined}
          */
         _computeNameOrDisplayName() {
             return this.name || this.display_name;
@@ -263,7 +271,12 @@ function factory(dependencies) {
         }),
         country: many2one('mail.country'),
         display_name: attr({
+            compute: '_computeDisplayName',
             default: "",
+            dependencies: [
+                'display_name',
+                'userDisplayName',
+            ],
         }),
         email: attr(),
         failureNotifications: one2many('mail.notification', {
@@ -304,6 +317,12 @@ function factory(dependencies) {
         user: one2one('mail.user', {
             inverse: 'partner',
         }),
+        /**
+         * Serves as compute dependency.
+         */
+        userDisplayName: attr({
+            related: 'user.display_name',
+        }),
     };
 
     Partner.modelName = 'mail.partner';
diff --git a/addons/mail/static/src/models/user/user.js b/addons/mail/static/src/models/user/user.js
index 18b2c28e1ac..7fc23b1e17f 100644
--- a/addons/mail/static/src/models/user/user.js
+++ b/addons/mail/static/src/models/user/user.js
@@ -84,17 +84,6 @@ function factory(dependencies) {
             });
         }
 
-        /**
-         * @returns {string}
-         */
-        nameOrDisplayName() {
-            const partner = this.partner;
-            if (!partner) {
-                return this.partnerDisplayName;
-            }
-            return partner.nameOrDisplayName;
-        }
-
         /**
          * Gets the chat between this user and the current user.
          *
@@ -195,25 +184,56 @@ function factory(dependencies) {
         }
 
         /**
-         * @override
+         * @private
+         * @returns {string|undefined}
          */
-        _updateAfter(previous) {
-            if (this.partnerDisplayName && this.partner) {
-                this.partner.update({ display_name: this.partnerDisplayName });
-            }
+        _computeDisplayName() {
+            return this.display_name || this.partner && this.partner.display_name;
         }
 
+        /**
+         * @private
+         * @returns {string|undefined}
+         */
+        _computeNameOrDisplayName() {
+            return this.partner && this.partner.nameOrDisplayName || this.display_name;
+        }
     }
 
     User.fields = {
         id: attr(),
+        display_name: attr({
+            compute: '_computeDisplayName',
+            dependencies: [
+                'display_name',
+                'partnerDisplayName',
+            ],
+        }),
         model: attr({
             default: 'res.user',
         }),
+        nameOrDisplayName: attr({
+            compute: '_computeNameOrDisplayName',
+            dependencies: [
+                'display_name',
+                'partnerNameOrDisplayName',
+            ]
+        }),
         partner: one2one('mail.partner', {
             inverse: 'user',
         }),
-        partnerDisplayName: attr(),
+        /**
+         * Serves as compute dependency.
+         */
+        partnerDisplayName: attr({
+            related: 'partner.display_name',
+        }),
+        /**
+         * Serves as compute dependency.
+         */
+        partnerNameOrDisplayName: attr({
+            related: 'partner.nameOrDisplayName',
+        }),
     };
 
     User.modelName = 'mail.user';