diff --git a/helpdesk/models.py b/helpdesk/models.py
index 44575f07..a258a315 100644
--- a/helpdesk/models.py
+++ b/helpdesk/models.py
@@ -36,8 +36,8 @@ import uuid
 def format_time_spent(time_spent):
     if time_spent:
         time_spent = "{0:02d}h:{1:02d}m".format(
-            time_spent.seconds // 3600,
-            time_spent.seconds % 3600 // 60
+            int(time_spent.total_seconds()) // 3600,
+            int(time_spent.total_seconds()) % 3600 // 60
         )
     else:
         time_spent = ""