diff --git a/lib/Doctrine/Collection/Iterator.php b/lib/Doctrine/Collection/Iterator.php
index d33777646..47b03a171 100644
--- a/lib/Doctrine/Collection/Iterator.php
+++ b/lib/Doctrine/Collection/Iterator.php
@@ -57,7 +57,7 @@ abstract class Doctrine_Collection_Iterator implements Iterator
      * constructor
      * @var Doctrine_Collection $collection
      */
-    public function __construct(Doctrine_Collection $collection)
+    public function __construct($collection)
     {
         $this->collection = $collection;
         $this->keys       = $this->collection->getKeys();