diff --git a/helpdesk_user_default_ticket_team/README.rst b/helpdesk_user_default_ticket_team/README.rst
index 13b3f76..0d10945 100644
--- a/helpdesk_user_default_ticket_team/README.rst
+++ b/helpdesk_user_default_ticket_team/README.rst
@@ -18,6 +18,14 @@ default helpdesk team per user. It provides:
   * If the assigned team has a default project, the ticket is also linked to
     that project.
 
+* Automatic user assignment when a team is selected:
+
+  * When a team is set or changed on a ticket, if the current assigned user
+    is not a member of that team, the team leader (``team_id.user_id``) is
+    automatically assigned instead.
+  * If the team has no leader configured, the assigned user is left unchanged
+    (to avoid creating unassigned tickets).
+
 This is particularly useful for multi-company or multi-team environments where
 portal users should always have their tickets routed to a specific team.
 
diff --git a/helpdesk_user_default_ticket_team/models/helpdesk_ticket.py b/helpdesk_user_default_ticket_team/models/helpdesk_ticket.py
index 7a90d10..dddd1fc 100644
--- a/helpdesk_user_default_ticket_team/models/helpdesk_ticket.py
+++ b/helpdesk_user_default_ticket_team/models/helpdesk_ticket.py
@@ -4,6 +4,14 @@ from odoo import api, models
 class HelpdeskTicket(models.Model):
     _inherit = "helpdesk.ticket"
 
+    @api.depends("team_id")
+    def _compute_user_id(self):
+        for ticket in self:
+            if ticket.team_id:
+                if ticket.user_id not in ticket.team_id.user_ids:
+                    if ticket.team_id.user_id:
+                        ticket.user_id = ticket.team_id.user_id
+
     @api.model_create_multi
     def create(self, vals_list):
         for vals in vals_list: