diff --git a/openpype/tools/attribute_defs/files_widget.py b/openpype/tools/attribute_defs/files_widget.py
index 738e50ba071..2c8ed729c23 100644
--- a/openpype/tools/attribute_defs/files_widget.py
+++ b/openpype/tools/attribute_defs/files_widget.py
@@ -155,7 +155,7 @@ def _update_items_label(self):
             extensions_label = " or ".join(allowed_items)
         else:
             last_item = allowed_items.pop(-1)
-            new_last_item = " or ".join(last_item, allowed_items.pop(-1))
+            new_last_item = " or ".join([last_item, allowed_items.pop(-1)])
             allowed_items.append(new_last_item)
             extensions_label = ", ".join(allowed_items)