diff --git a/juju/client/connector.py b/juju/client/connector.py
index e51f610cc..a5998c6a3 100644
--- a/juju/client/connector.py
+++ b/juju/client/connector.py
@@ -80,6 +80,18 @@ async def connect(self, **kwargs):
         else:
             if self._connection:
                 await self._connection.close()
+
+            account = kwargs.pop('account', {})
+            # Prioritize the username and password that user provided
+            # If not enough, try to patch it with info from accounts.yaml
+            if 'username' not in kwargs and account.get('user'):
+                kwargs.update(username=account.get('user'))
+            if 'password' not in kwargs and account.get('password'):
+                kwargs.update(password=account.get('password'))
+
+            if not ({'username', 'password'}.issubset(kwargs)):
+                required = {'username', 'password'}.difference(kwargs)
+                raise ValueError(f'Some authentication parameters are required : {",".join(required)}')
             self._connection = await Connection.connect(**kwargs)
 
         if not self.controller_name:
@@ -103,7 +115,7 @@ async def disconnect(self):
             await self._log_connection.close()
             self._log_connection = None
 
-    async def connect_controller(self, controller_name=None, specified_facades=None):
+    async def connect_controller(self, controller_name=None, specified_facades=None, **kwargs):
         """Connect to a controller by name. If the name is empty, it
         connect to the current controller.
         """
@@ -118,16 +130,15 @@ async def connect_controller(self, controller_name=None, specified_facades=None)
 
         proxy = proxy_from_config(controller.get('proxy-config', None))
 
-        await self.connect(
-            endpoint=endpoints,
-            uuid=None,
-            username=accounts.get('user'),
-            password=accounts.get('password'),
-            cacert=controller.get('ca-cert'),
-            bakery_client=self.bakery_client_for_controller(controller_name),
-            specified_facades=specified_facades,
-            proxy=proxy,
-        )
+        kwargs.update(endpoint=endpoints,
+                      uuid=None,
+                      account=accounts,
+                      cacert=controller.get('ca-cert'),
+                      bakery_client=self.bakery_client_for_controller(controller_name),
+                      specified_facades=specified_facades,
+                      proxy=proxy,
+                      )
+        await self.connect(**kwargs)
         self.controller_name = controller_name
         self.controller_uuid = controller["uuid"]
 
@@ -176,8 +187,7 @@ async def connect_model(self, model_name=None, **kwargs):
         # JujuData.
         kwargs.update(endpoint=endpoints,
                       uuid=model_uuid,
-                      username=account.get('user'),
-                      password=account.get('password'),
+                      account=account,
                       cacert=controller.get('ca-cert'),
                       bakery_client=self.bakery_client_for_controller(controller_name),
                       proxy=proxy)