diff --git a/client/ayon_core/tools/push_to_project/models/integrate.py b/client/ayon_core/tools/push_to_project/models/integrate.py
index 197cefe819..c512d3ef68 100644
--- a/client/ayon_core/tools/push_to_project/models/integrate.py
+++ b/client/ayon_core/tools/push_to_project/models/integrate.py
@@ -1153,7 +1153,7 @@ class ProjectPushItemProcess:
                 {"active": False}
             )
 
-    def _copy_version_thumbnail(self):
+    def _copy_version_thumbnail(self) -> Optional[str]:
         thumbnail_id = self._src_version_entity["thumbnailId"]
         if not thumbnail_id:
             return None