diff --git a/telethon/events/chataction.py b/telethon/events/chataction.py
index 1a67394b..339472a2 100644
--- a/telethon/events/chataction.py
+++ b/telethon/events/chataction.py
@@ -83,6 +83,9 @@ class ChatAction(EventBuilder):
         Represents the event of a new chat action.
 
         Members:
+            action_message  (:tl:`MessageAction`):
+                The message invoked by this Chat Action.
+
             new_pin (`bool`):
                 ``True`` if there is a new pin.