diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index b704979de85..12bbac57459 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -312,9 +312,10 @@ class Lead(models.Model):
         if vals.get('user_id') and 'date_open' not in vals:
             vals['date_open'] = fields.Datetime.now()
 
-        if context.get('default_partner_id') and not vals.get('email_from'):
-            partner = self.env['res.partner'].browse(context['default_partner_id'])
-            vals['email_from'] = partner.email
+        partner_id = vals.get('partner_id') or context.get('default_partner_id')
+        onchange_values = self._onchange_partner_id_values(partner_id)
+        onchange_values.update(vals)  # we don't want to overwrite any existing key
+        vals = onchange_values
 
         # context: no_log, because subtype already handle this
         return super(Lead, self.with_context(context, mail_create_nolog=True)).create(vals)
diff --git a/addons/website_crm_partner_assign/tests/test_partner_assign.py b/addons/website_crm_partner_assign/tests/test_partner_assign.py
index 137cd773c33..4bab904b3b8 100644
--- a/addons/website_crm_partner_assign/tests/test_partner_assign.py
+++ b/addons/website_crm_partner_assign/tests/test_partner_assign.py
@@ -16,6 +16,19 @@ class TestPartnerAssign(TransactionCase):
     def setUp(self):
         super(TestPartnerAssign, self).setUp()
 
+        self.customer_uk = self.env['res.partner'].create({
+            'name': 'Nigel',
+            'country_id': self.env.ref('base.uk').id,
+            'city': 'Birmingham',
+            'zip': 'B46 3AG',
+            'street': 'Cannon Hill Park',
+        })
+        self.lead_uk = self.env['crm.lead'].create({
+            'type': 'opportunity',
+            'name': 'Office Design and Architecture',
+            'partner_id': self.customer_uk.id
+        })
+
         def geo_find(addr, apikey):
             return {
                 'Wavre, Belgium': (50.7158956, 4.6128075),
@@ -51,7 +64,7 @@ class TestPartnerAssign(TransactionCase):
             "partner_weight": 10,
         })
 
-        lead = self.env.ref('crm.crm_case_21')
+        lead = self.lead_uk
 
         # In order to test find nearest Partner functionality and assign to opportunity,
         # I Set Geo Lattitude and Longitude according to partner address.