diff --git a/pulsar-client-cpp/python/pulsar/schema/schema.py b/pulsar-client-cpp/python/pulsar/schema/schema.py
index 91250a8492289..260d7b05ef6de 100644
--- a/pulsar-client-cpp/python/pulsar/schema/schema.py
+++ b/pulsar-client-cpp/python/pulsar/schema/schema.py
@@ -80,7 +80,7 @@ def __init__(self, record_cls):
 
     def encode(self, obj):
         self._validate_object_type(obj)
-        return json.dumps(obj.__dict__, indent=True).encode('utf-8')
+        return json.dumps(obj.__dict__, default=lambda o: o.__dict__, indent=True).encode('utf-8')
 
     def decode(self, data):
         return self._record_cls(**json.loads(data))