diff --git a/src/pylero/work_item.py b/src/pylero/work_item.py
index fd45561..b6c0c68 100644
--- a/src/pylero/work_item.py
+++ b/src/pylero/work_item.py
@@ -1468,7 +1468,7 @@ def get_custom_fields(cls, project_id):
             if cft.required:
                 cls._required_fields.append(local_name)
         cls._got_custom_fields = True
-        return None
+        return cls._all_custom_fields, cls._required_fields
 
     @classmethod
     def query(