diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index adcc5b1f382..50f4f1a9e48 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -2350,7 +2350,6 @@ class MailThread(models.AbstractModel):
 
         return True
 
-    @api.model
     def _notify_by_email_prepare_rendering_context(self, message, msg_vals=False, model_description=False,
                                                    force_email_company=False, force_email_lang=False):
         """ Prepare rendering context for notification email.