diff --git a/oslo/messaging/_drivers/impl_zmq.py b/oslo/messaging/_drivers/impl_zmq.py
index af5b612b2..90ac92fee 100644
--- a/oslo/messaging/_drivers/impl_zmq.py
+++ b/oslo/messaging/_drivers/impl_zmq.py
@@ -230,7 +230,7 @@ class ZmqClient(object):
                            (msg_id, topic, 'cast', _serialize(data))))
             return
 
-        rpc_envelope = rpc_common.serialize_msg(data[1], envelope)
+        rpc_envelope = rpc_common.serialize_msg(data[1])
         zmq_msg = moves.reduce(lambda x, y: x + y, rpc_envelope.items())
         self.outq.send(map(bytes,
                        (msg_id, topic, 'impl_zmq_v2', data[0]) + zmq_msg))