diff --git a/traitlets/traitlets.py b/traitlets/traitlets.py
index fa883de4..c063961c 100644
--- a/traitlets/traitlets.py
+++ b/traitlets/traitlets.py
@@ -1374,7 +1374,7 @@ def _register_validator(self, handler, names):
             if hasattr(self, magic_name):
                 class_value = getattr(self.__class__, magic_name)
                 if not isinstance(class_value, ValidateHandler):
-                    _deprecated_method(class_value, self.__class, magic_name,
+                    _deprecated_method(class_value, self.__class__, magic_name,
                         "use @validate decorator instead.")
         for name in names:
             self._trait_validators[name] = handler