diff --git a/addons/mail/mail_thread.py b/addons/mail/mail_thread.py
index 8aaed056559..f3e1354c5eb 100644
--- a/addons/mail/mail_thread.py
+++ b/addons/mail/mail_thread.py
@@ -87,6 +87,8 @@ class mail_thread(osv.osv):
         return thread_id;
     
     def write(self, cr, uid, ids, vals, context=None):
+        if isinstance(ids, ('int', 'long')):
+            ids = [ids]
         write_res = super(mail_thread, self).write(cr, uid, ids, vals, context=context);
         if write_res:
             self.message_subscribe(cr, uid, ids, [uid], context=context)