diff --git a/src/Query/FunctionScoreQuery.php b/src/Query/FunctionScoreQuery.php
index 9e09a52a3dea7a3bf89c737526275a58c6be8c28..d7d6c6e10f6147d2417d3934659f02d21cd0f0c4 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);