diff --git a/src/Sort/FieldSort.php b/src/Sort/FieldSort.php
index c9ae2d621e1301e31382dd67ae79d4c2e9ce3ad3..573dff69642540d2411825e2a8badbad5f05d175 100644
--- a/src/Sort/FieldSort.php
+++ b/src/Sort/FieldSort.php
@@ -91,7 +91,7 @@ class FieldSort implements BuilderInterface
         }
 
         $output = [
-            $this->field => $fieldValues,
+            $this->field => empty($fieldValues) ? new \stdClass() : $fieldValues,
         ];
 
         return $output;