diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -196,12 +196,14 @@
             last = root.prev
             link.prev = last
             link.next = root
-            last.next = root.prev = link
+            last.next = link
+            root.prev = proxy(link)
         else:
             first = root.next
             link.prev = root
             link.next = first
-            root.next = first.prev = link
+            root.next = link
+            first.prev = proxy(link)
 
     def __sizeof__(self):
         sizeof = _sys.getsizeof