diff --git a/addons/email_template/tests/test_mail.py b/addons/email_template/tests/test_mail.py
index 73dbe28114c..80b9dcee5a2 100644
--- a/addons/email_template/tests/test_mail.py
+++ b/addons/email_template/tests/test_mail.py
@@ -165,6 +165,7 @@ class test_message_compose(TestMailBase):
         message_pigs_pids = [partner.id for partner in message_pigs.notified_partner_ids]
         message_bird_pids = [partner.id for partner in message_bird.notified_partner_ids]
         partner_ids = self.res_partner.search(cr, uid, [('email', 'in', ['b@b.b', 'c@c.c', 'd@d.d'])])
+        partner_ids.append(p_a_id)
         self.assertEqual(set(message_pigs_pids), set(partner_ids), 'mail.message on pigs incorrect number of notified_partner_ids')
         self.assertEqual(set(message_bird_pids), set(partner_ids), 'mail.message on bird notified_partner_ids incorrect')
 
diff --git a/addons/mail/mail_message.py b/addons/mail/mail_message.py
index d545f3782b4..d80b65ed648 100644
--- a/addons/mail/mail_message.py
+++ b/addons/mail/mail_message.py
@@ -849,9 +849,7 @@ class mail_message(osv.Model):
         # message has no subtype_id: pure log message -> no partners, no one notified
         if not message.subtype_id:
             return True
-        # all partner_ids of the mail.message have to be notified
-        if message.partner_ids:
-            partners_to_notify |= set(message.partner_ids)
+            
         # all followers of the mail.message document have to be added as partners and notified
         if message.model and message.res_id:
             fol_obj = self.pool.get("mail.followers")
@@ -866,7 +864,11 @@ class mail_message(osv.Model):
         if message.author_id and message.model == "res.partner" and message.res_id == message.author_id.id:
             partners_to_notify |= set([message.author_id])
         elif message.author_id:
-            partners_to_notify = partners_to_notify - set([message.author_id])
+            partners_to_notify -= set([message.author_id])
+
+        # all partner_ids of the mail.message have to be notified regardless of the above (even the author if explicitly added!)
+        if message.partner_ids:
+            partners_to_notify |= set(message.partner_ids)
 
         # notify
         if partners_to_notify: