diff --git a/src/Query/FunctionScoreQuery.php b/src/Query/FunctionScoreQuery.php
index 19522eda489bb4fe92c130361c5b24d2042dfbe9..68f51b49f105dd6f58f42822574998579d2f9adc 100644
--- a/src/Query/FunctionScoreQuery.php
+++ b/src/Query/FunctionScoreQuery.php
@@ -162,7 +162,7 @@ class FunctionScoreQuery implements BuilderInterface
     public function addRandomFunction($seed = null, BuilderInterface $filter = null)
     {
         $function = [
-            'random_score' => $seed ? [ 'seed' => $seed ] : [],
+            'random_score' => $seed ? [ 'seed' => $seed ] : new \stdClass(),
         ];
 
         $this->applyFilter($function, $filter);