diff --git a/qutebrowser/utils/__init__.py b/qutebrowser/utils/__init__.py
index 0b9320617..86f7d089e 100644
--- a/qutebrowser/utils/__init__.py
+++ b/qutebrowser/utils/__init__.py
@@ -71,8 +71,9 @@ def version():
 
 def is_about_url(url):
     """Return True if url is an about:... or other special URL."""
-    url = qurl(url)
-    return url.toString().replace('http://', '').startswith('about:')
+    if isinstance(url, QUrl):
+        url = url.toString()
+    return url.replace('http://', '').startswith('about:')
 
 
 def _git_str():