diff --git a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
index 2a3ec0ee477b..0bde3e119227 100644
--- a/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
+++ b/src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php
@@ -514,11 +514,13 @@ protected function mutateAttributeForArray($key, $value)
      * Merge new casts with existing casts on the model.
      *
      * @param  array  $casts
-     * @return void
+     * @return $this
      */
     public function mergeCasts($casts)
     {
         $this->casts = array_merge($this->casts, $casts);
+
+        return $this;
     }
 
     /**