diff --git a/telethon/extensions/tcp_client.py b/telethon/extensions/tcp_client.py
index <HASH>..<HASH> 100644
--- a/telethon/extensions/tcp_client.py
+++ b/telethon/extensions/tcp_client.py
@@ -56,12 +56,7 @@ class TcpClient:
         :param port: the port to connect to.
         """
         if ':' in ip:  # IPv6
-            # The address needs to be surrounded by [] as discussed on PR#425
-            if not ip.startswith('['):
-                ip = '[' + ip
-            if not ip.endswith(']'):
-                ip = ip + ']'
-
+            ip = ip.replace('[', '').replace(']', '')
             mode, address = socket.AF_INET6, (ip, port, 0, 0)
         else:
             mode, address = socket.AF_INET, (ip, port)
Remove square braces from IPv6 addresses (#<I>)