diff --git a/addons/hr/hr.py b/addons/hr/hr.py
index 5bb172eb082..85366adfe3b 100644
--- a/addons/hr/hr.py
+++ b/addons/hr/hr.py
@@ -349,10 +349,12 @@ class hr_employee(osv.osv):
         else:
             return super(hr_employee, self).get_suggested_thread(cr, uid, removed_suggested_threads, context)
 
-    def _message_get_auto_subscribe_fields(self, cr, uid, updated_fields, auto_follow_fields=['user_id'], context=None):
+    def _message_get_auto_subscribe_fields(self, cr, uid, updated_fields, auto_follow_fields=None, context=None):
         """ Overwrite of the original method to always follow user_id field,
         even when not track_visibility so that a user will follow it's employee
         """
+        if auto_follow_fields is None:
+            auto_follow_fields = ['user_id']
         user_field_lst = []
         for name, column_info in self._all_columns.items():
             if name in auto_follow_fields and name in updated_fields and column_info.column._obj == 'res.users':
diff --git a/addons/mail/mail_thread.py b/addons/mail/mail_thread.py
index 55a566880b8..dc2b98fdc93 100644
--- a/addons/mail/mail_thread.py
+++ b/addons/mail/mail_thread.py
@@ -1699,7 +1699,7 @@ class mail_thread(osv.AbstractModel):
             ], context=context)
         return fol_obj.unlink(cr, SUPERUSER_ID, fol_ids, context=context)
 
-    def _message_get_auto_subscribe_fields(self, cr, uid, updated_fields, auto_follow_fields=['user_id'], context=None):
+    def _message_get_auto_subscribe_fields(self, cr, uid, updated_fields, auto_follow_fields=None, context=None):
         """ Returns the list of relational fields linking to res.users that should
             trigger an auto subscribe. The default list checks for the fields
             - called 'user_id'
@@ -1710,6 +1710,8 @@ class mail_thread(osv.AbstractModel):
             Override this method if a custom behavior is needed about fields
             that automatically subscribe users.
         """
+        if auto_follow_fields is None:
+            auto_follow_fields = ['user_id']
         user_field_lst = []
         for name, column_info in self._all_columns.items():
             if name in auto_follow_fields and name in updated_fields and getattr(column_info.column, 'track_visibility', False) and column_info.column._obj == 'res.users':
diff --git a/addons/project/project.py b/addons/project/project.py
index d98b9b03e94..a9c487be244 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -782,6 +782,7 @@ class task(osv.osv):
                 'project.task': (lambda self, cr, uid, ids, c={}: ids, ['work_ids', 'remaining_hours', 'planned_hours'], 10),
                 'project.task.work': (_get_task, ['hours'], 10),
             }),
+        'reviewer_id': fields.many2one('res.users', 'Reviewer', select=True, track_visibility='onchange'),
         'user_id': fields.many2one('res.users', 'Assigned to', select=True, track_visibility='onchange'),
         'delegated_user_id': fields.related('child_ids', 'user_id', type='many2one', relation='res.users', string='Delegated To'),
         'partner_id': fields.many2one('res.partner', 'Customer'),
@@ -801,6 +802,7 @@ class task(osv.osv):
         'progress': 0,
         'sequence': 10,
         'active': True,
+        'reviewer_id': lambda obj, cr, uid, ctx=None: uid,
         'user_id': lambda obj, cr, uid, ctx=None: uid,
         'company_id': lambda self, cr, uid, ctx=None: self.pool.get('res.company')._company_default_get(cr, uid, 'project.task', context=ctx),
         'partner_id': lambda self, cr, uid, ctx=None: self._get_default_partner(cr, uid, context=ctx),
@@ -1090,6 +1092,11 @@ class task(osv.osv):
     # Mail gateway
     # ---------------------------------------------------
 
+    def _message_get_auto_subscribe_fields(self, cr, uid, updated_fields, auto_follow_fields=None, context=None):
+        if auto_follow_fields is None:
+            auto_follow_fields = ['user_id', 'reviewer_id']
+        return super(task, self)._message_get_auto_subscribe_fields(cr, uid, updated_fields, auto_follow_fields, context=context)
+
     def message_get_reply_to(self, cr, uid, ids, context=None):
         """ Override to get the reply_to of the parent project. """
         return [task.project_id.message_get_reply_to()[0] if task.project_id else False
diff --git a/addons/project/project_view.xml b/addons/project/project_view.xml
index b6a839edcf6..693e1b47f13 100644
--- a/addons/project/project_view.xml
+++ b/addons/project/project_view.xml
@@ -29,9 +29,11 @@
                         help="Show only tasks having a deadline"/>
                     <field name="partner_id"/>
                     <field name="project_id"/>
+                    <field name="reviewer_id"/>
                     <field name="user_id"/>
                     <field name="stage_id" domain="[]"/>
                     <group expand="0" string="Group By...">
+                        <filter string="Reviewers" name="group_reviewer_id" domain="[]"  context="{'group_by':'reviewer_id'}"/>
                         <filter string="Users" name="group_user_id" icon="terp-personal" domain="[]"  context="{'group_by':'user_id'}"/>
                         <filter string="Project" name="group_project_id" icon="terp-folder-violet" domain="[]" context="{'group_by':'project_id'}"/>
                         <filter string="Stage" name="group_stage_id" icon="terp-stage" domain="[]" context="{'group_by':'stage_id'}"/>
@@ -389,6 +391,9 @@
                             <field name="user_id"
                                 options='{"no_open": True}'
                                 context="{'default_groups_ref': ['base.group_user', 'base.group_partner_manager', 'project.group_project_user']}"/>
+                            <field name="reviewer_id"
+                                options='{"no_open": True}'
+                                context="{'default_groups_ref': ['base.group_user', 'base.group_partner_manager', 'project.group_project_user']}"/>
                             <field name="planned_hours" widget="float_time"
                                     groups="project.group_time_work_estimation_tasks"
                                     on_change="onchange_planned(planned_hours, effective_hours)"/>