diff --git a/Lib/urllib2.py b/Lib/urllib2.py
index e90b61f..8d38504 100644
--- a/Lib/urllib2.py
+++ b/Lib/urllib2.py
@@ -858,7 +858,7 @@
             auth_val = 'Digest %s' % auth
             if req.headers.get(self.auth_header, None) == auth_val:
                 return None
-            req.add_header(self.auth_header, auth_val)
+            req.add_unredirected_header(self.auth_header, auth_val)
             resp = self.parent.open(req)
             return resp