diff --git a/flask/app.py b/flask/app.py
index f2ec45e9..01b8adfe 100644
--- a/flask/app.py
+++ b/flask/app.py
@@ -529,8 +529,17 @@ class Flask(_PackageBoundObject):
         rule = Rule(rule, methods=methods, **options)
         rule.provide_automatic_options = provide_automatic_options
         self.url_map.add(rule)
+        endpoint_override = None
+        try:
+            rules_before_added = self.url_map._rules[:-1]
+            ix = rules_before_added.index(rule)
+            endpoint_override = rules_before_added[ix].endpoint
+        except ValueError:
+            pass
         if view_func is not None:
             self.view_functions[endpoint] = view_func
+            if endpoint_override:
+                self.view_functions[endpoint_override] = view_func
 
     def route(self, rule, **options):
         """A decorator that is used to register a view function for a