diff --git a/pydal/objects.py b/pydal/objects.py
index e4debde40..4aad47716 100644
--- a/pydal/objects.py
+++ b/pydal/objects.py
@@ -186,6 +186,12 @@ def __getitem__(self, k):
 
         raise KeyError(key)
 
+    def __contains__(self, k):
+        key = str(k)
+
+        _extra = BasicStorage.get(self, "_extra", None)
+        return (_extra is not None and k in _extra) or BasicStorage.__contains__(self, key)
+
     def __repr__(self):
         return "<Row %s>" % self.as_dict(custom_types=[LazySet])