diff --git a/src/Illuminate/Foundation/helpers.php b/src/Illuminate/Foundation/helpers.php
index 6bed4ce2731d..ddf3039c22a2 100644
--- a/src/Illuminate/Foundation/helpers.php
+++ b/src/Illuminate/Foundation/helpers.php
@@ -906,6 +906,10 @@ function trans_choice($key, $number, array $replace = [], $locale = null)
      */
     function __($key = null, $replace = [], $locale = null)
     {
+        if (is_null($key)) {
+            return $key;
+        }
+
         return trans($key, $replace, $locale);
     }
 }