diff --git a/chatbase/base_message.py b/chatbase/base_message.py
index 13c3d02..1cc1787 100644
--- a/chatbase/base_message.py
+++ b/chatbase/base_message.py
@@ -49,6 +49,7 @@ def __init__(self,
                  intent="",
                  version="",
                  user_id="",
+                 session_id="",
                  type=None,
                  not_handled=False,
                  time_stamp=None):
@@ -58,6 +59,7 @@ def __init__(self,
         self.intent = intent
         self.version = version
         self.user_id = user_id
+        self.custom_session_id = session_id
         self.not_handled = not_handled
         self.feedback = False
         self.time_stamp = time_stamp or Message.get_current_timestamp()