diff --git a/discogs_client/client.py b/discogs_client/client.py
index 536f7b6..e693563 100644
--- a/discogs_client/client.py
+++ b/discogs_client/client.py
@@ -50,6 +50,7 @@ def get_authorize_url(self, callback_url=None):
 
         params = {}
         params['User-Agent'] = self.user_agent
+        params['Content-Type'] = 'application/x-www-form-urlencoded'
         if callback_url:
             params['oauth_callback'] = callback_url
         postdata = urlencode(params)