diff -r 5d70ac83d104 Lib/http/client.py
--- a/Lib/http/client.py	Thu Jul 24 12:44:07 2014 +0200
+++ b/Lib/http/client.py	Thu Jul 24 16:34:46 2014 -0700
@@ -835,8 +835,7 @@
         if self.sock:
             raise RuntimeError("Can't set up tunnel for established connection")
 
-        self._tunnel_host = host
-        self._tunnel_port = port
+        self._tunnel_host, self._tunnel_port = self._get_hostport(host, port)
         if headers:
             self._tunnel_headers = headers
         else:
diff -r 5d70ac83d104 Lib/test/test_httplib.py
--- a/Lib/test/test_httplib.py	Thu Jul 24 12:44:07 2014 +0200
+++ b/Lib/test/test_httplib.py	Thu Jul 24 16:34:46 2014 -0700
@@ -1235,6 +1235,11 @@
         conn.set_tunnel('destination.com')
         conn.request('HEAD', '/', '')
 
+        try:
+            int(conn._tunnel_port)
+        except TypeError:
+            self.fail('Invalid tunnel port value')
+
         self.assertEqual(conn.sock.host, 'proxy.com')
         self.assertEqual(conn.sock.port, 80)
         self.assertTrue(b'CONNECT destination.com' in conn.sock.data)