diff --git a/pyrogram/client/types/audio.py b/pyrogram/client/types/audio.py
index d2e53f44..10febb4b 100644
--- a/pyrogram/client/types/audio.py
+++ b/pyrogram/client/types/audio.py
@@ -5,7 +5,7 @@ class Audio:
                  performer: str = None,
                  title: str = None,
                  mime_type: str = None,
-                 file_size: str = None):
+                 file_size: int = None):
         self.file_id = file_id
         self.duration = duration
         self.performer = performer