diff --git a/couchdb/mapping.py b/couchdb/mapping.py
index bedddc13..ad47b7b6 100644
--- a/couchdb/mapping.py
+++ b/couchdb/mapping.py
@@ -99,6 +99,8 @@ def __get__(self, instance, owner):
             if callable(default):
                 default = default()
             value = default
+            if self.name in owner.__dict__.keys():
+                instance._data[self.name] = value
         return value
 
     def __set__(self, instance, value):