diff --git a/addons/website_mail/views/website_mail.xml b/addons/website_mail/views/website_mail.xml
index 2e246ac18c2..a0d4b4e85a2 100644
--- a/addons/website_mail/views/website_mail.xml
+++ b/addons/website_mail/views/website_mail.xml
@@ -40,8 +40,10 @@
                 :chatter_mode string: 'json' or 'post' depending on what kind of request you want
         -->
         <section id="discussion" class="hidden-print oe_website_portal o_website_mail_thread">
-            <section class="mb32 css_editable_mode_hidden hidden-print">
-                <form class="o_website_chatter_form" t-attf-action="/website_mail/post/#{chatter_mode}" method="POST" t-if="website.env.user != request.env['ir.model.data'].xmlid_to_object('base.public_user') or token or sha_in">
+            <t t-set="is_user_public" t-value="website.env.user == request.website.user_id"/>
+            <t t-set="can_comment" t-value="sha_in or token or not is_user_public"/>
+            <section class="mb32 hidden-print" t-if="can_comment">
+                <form class="o_website_chatter_form" t-attf-action="/website_mail/post/#{chatter_mode}" method="POST">
                     <img class="img pull-left img-circle" t-attf-src="/web/image/res.partner/#{user_id.partner_id.id}/image_small/50x50" style="width: 50px; margin-right: 10px;"/>
                     <div class="pull-left mb32" style="width: 75%%">
                         <textarea rows="4" name="message" class="form-control" placeholder="Write a message..."></textarea>
@@ -58,6 +60,10 @@
                     </div>
                 </form>
             </section>
+            <section class="mb32 hidden-print" t-if="not can_comment">
+                <h3>Leave a comment</h3>
+                <p>You must be <a t-attf-href="/web/login?redirect=#{quote_plus(request.httprequest.url + '#discussion')}">logged in</a> to post a comment.</p>
+            </section>
             <div class="clearfix"/>
             <ul class="media-list o_website_comments">
                 <t t-foreach="object.message_ids" t-as="message">