diff --git a/lib/Twig/Loader/Array.php b/lib/Twig/Loader/Array.php
index 7e7f556aa..a5d9f7a4f 100644
--- a/lib/Twig/Loader/Array.php
+++ b/lib/Twig/Loader/Array.php
@@ -21,7 +21,7 @@
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */
-class Twig_Loader_Array implements Twig_LoaderInterface
+class Twig_Loader_Array implements Twig_LoaderInterface, Twig_ExistsLoaderInterface
 {
     private $templates = array();
 
diff --git a/lib/Twig/Loader/Chain.php b/lib/Twig/Loader/Chain.php
index ec21572ab..9244cbe01 100644
--- a/lib/Twig/Loader/Chain.php
+++ b/lib/Twig/Loader/Chain.php
@@ -14,7 +14,7 @@
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */
-class Twig_Loader_Chain implements Twig_LoaderInterface
+class Twig_Loader_Chain implements Twig_LoaderInterface, Twig_ExistsLoaderInterface
 {
     private $hasSourceCache = array();
     private $loaders = array();
diff --git a/lib/Twig/Loader/Filesystem.php b/lib/Twig/Loader/Filesystem.php
index 0f791df83..179f95a16 100644
--- a/lib/Twig/Loader/Filesystem.php
+++ b/lib/Twig/Loader/Filesystem.php
@@ -14,7 +14,7 @@
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */
-class Twig_Loader_Filesystem implements Twig_LoaderInterface
+class Twig_Loader_Filesystem implements Twig_LoaderInterface, Twig_ExistsLoaderInterface
 {
     /** Identifier of the main namespace. */
     const MAIN_NAMESPACE = '__main__';