Index: django/utils/timesince.py
===================================================================
--- django/utils/timesince.py	(revision 9033)
+++ django/utils/timesince.py	(working copy)
@@ -29,6 +29,9 @@
     if d.__class__ is not datetime.datetime:
         d = datetime.datetime(d.year, d.month, d.day)
 
+    if now and now.__class__ is not datetime.datetime:
+        now = datetime.datetime(now.year, now.month, now.day)
+
     if not now:
         if d.tzinfo:
             now = datetime.datetime.now(LocalTimezone(d))