diff --git a/django/contrib/admin/widgets.py b/django/contrib/admin/widgets.py
index e7c95fb219..a6269376ef 100644
--- a/django/contrib/admin/widgets.py
+++ b/django/contrib/admin/widgets.py
@@ -137,6 +137,6 @@ class RelatedFieldWidgetWrapper(object):
         return u''.join(output)
 
     def __deepcopy__(self, memo):
-        # There is no reason to deepcopy self.admin_site, etc, so just return
-        # a shallow copy.
-        return copy.copy(self)
+        # There's no reason to deepcopy admin_site, etc, so just return self.
+        memo[id(self)] = self
+        return self