diff --git a/src/Webflow/Api.php b/src/Webflow/Api.php
index 9e5bdcd..5c46f9f 100644
--- a/src/Webflow/Api.php
+++ b/src/Webflow/Api.php
@@ -174,7 +174,9 @@ public function createItem(string $collectionId, array $fields)
 
     public function updateItem(string $collectionId, string $itemId, array $fields)
     {
-        return $this->put("/collections/{$collectionId}/items/{$itemId}", $fields);
+        return $this->put("/collections/{$collectionId}/items/{$itemId}", [
+            'fields' => $fields,
+        ]);
     }
 
     public function removeItem(string $collectionId, $itemId)