diff --git a/django/contrib/auth/models.py b/django/contrib/auth/models.py
index f686d90e7a..6fe781a041 100644
--- a/django/contrib/auth/models.py
+++ b/django/contrib/auth/models.py
@@ -273,7 +273,7 @@ class AnonymousUser(object):
         pass
 
     def __str__(self):
-        return 'AnonymousUser'
+        return _('AnonymousUser')
 
     def __eq__(self, other):
         return isinstance(other, self.__class__)
diff --git a/django/template/defaultfilters.py b/django/template/defaultfilters.py
index a025365c90..bbaceba24a 100644
--- a/django/template/defaultfilters.py
+++ b/django/template/defaultfilters.py
@@ -2,7 +2,7 @@
 
 from django.template import resolve_variable, Library
 from django.conf import settings
-from django.utils.translation import gettext
+from django.utils.translation import gettext, ngettext
 import re
 import random as random_module
 
@@ -517,12 +517,12 @@ def filesizeformat(bytes):
         return "0 bytes"
         
     if bytes < 1024:
-        return "%d byte%s" % (bytes, bytes != 1 and 's' or '')
+        return ngettext("%(size)d byte", "%(size)d bytes", bytes) % {'size': bytes}
     if bytes < 1024 * 1024:
-        return "%.1f KB" % (bytes / 1024)
+        return gettext("%.1f KB") % (bytes / 1024)
     if bytes < 1024 * 1024 * 1024:
-        return "%.1f MB" % (bytes / (1024 * 1024))
-    return "%.1f GB" % (bytes / (1024 * 1024 * 1024))
+        return gettext("%.1f MB") % (bytes / (1024 * 1024))
+    return gettext("%.1f GB") % (bytes / (1024 * 1024 * 1024))
 
 def pluralize(value, arg='s'):
     """