diff --git a/telethon/extensions/tcp_client.py b/telethon/extensions/tcp_client.py
index 5255513a..3f803e63 100644
--- a/telethon/extensions/tcp_client.py
+++ b/telethon/extensions/tcp_client.py
@@ -59,7 +59,7 @@ class TcpClient:
                     raise
 
     def _get_connected(self):
-        return self._socket is not None
+        return self._socket is not None and self._socket.fileno() > 0
 
     connected = property(fget=_get_connected)