diff --git a/django/contrib/auth/backends.py b/django/contrib/auth/backends.py
index ac86749e53..0ddbd9ca77 100644
--- a/django/contrib/auth/backends.py
+++ b/django/contrib/auth/backends.py
@@ -134,7 +134,6 @@ class ModelBackend(BaseBackend):
                 'The `perm` argument must be a string or a permission instance.'
             )
 
-        UserModel = get_user_model()
         if obj is not None:
             return UserModel._default_manager.none()