diff --git a/src/Symfony/Component/HttpFoundation/JsonResponse.php b/src/Symfony/Component/HttpFoundation/JsonResponse.php
index 15e7b582f7..83a607cd6e 100644
--- a/src/Symfony/Component/HttpFoundation/JsonResponse.php
+++ b/src/Symfony/Component/HttpFoundation/JsonResponse.php
@@ -111,7 +111,7 @@ class JsonResponse extends Response
             // Not using application/javascript for compatibility reasons with older browsers.
             $this->headers->set('Content-Type', 'text/javascript');
 
-            return $this->setContent(sprintf('%s(%s);', $this->callback, $this->data));
+            return $this->setContent(sprintf('/**/%s(%s);', $this->callback, $this->data));
         }
 
         // Only set the header when there is none or when it equals 'text/javascript' (from a previous update with callback)
diff --git a/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php b/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
index ef392ca59d..2cb6b68550 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/JsonResponseTest.php
@@ -155,7 +155,7 @@ class JsonResponseTest extends \PHPUnit_Framework_TestCase
     {
         $response = JsonResponse::create(array('foo' => 'bar'))->setCallback('callback');
 
-        $this->assertEquals('callback({"foo":"bar"});', $response->getContent());
+        $this->assertEquals('/**/callback({"foo":"bar"});', $response->getContent());
         $this->assertEquals('text/javascript', $response->headers->get('Content-Type'));
     }