diff --git a/lib/Doctrine/ORM/OptimisticLockException.php b/lib/Doctrine/ORM/OptimisticLockException.php
index cadf4ce28..ecd5445b7 100644
--- a/lib/Doctrine/ORM/OptimisticLockException.php
+++ b/lib/Doctrine/ORM/OptimisticLockException.php
@@ -73,8 +73,8 @@ class OptimisticLockException extends ORMException
      */
     public static function lockFailedVersionMismatch($entity, $expectedLockVersion, $actualLockVersion)
     {
-        $expectedLockVersion = (is_object($expectedLockVersion) && $expectedLockVersion instanceof \DateTime) ? $expectedLockVersion->getTimestamp() : $expectedLockVersion;
-        $actualLockVersion = (is_object($actualLockVersion) && $actualLockVersion instanceof \DateTime) ? $actualLockVersion->getTimestamp() : $actualLockVersion;
+        $expectedLockVersion = ($expectedLockVersion instanceof \DateTime) ? $expectedLockVersion->getTimestamp() : $expectedLockVersion;
+        $actualLockVersion = ($actualLockVersion instanceof \DateTime) ? $actualLockVersion->getTimestamp() : $actualLockVersion;
         return new self("The optimistic lock failed, version " . $expectedLockVersion . " was expected, but is actually ".$actualLockVersion, $entity);
     }