diff --git a/oembed/templatetags/oembed_tags.py b/oembed/templatetags/oembed_tags.py
index 2b1dcba..6b2bf38 100644
--- a/oembed/templatetags/oembed_tags.py
+++ b/oembed/templatetags/oembed_tags.py
@@ -4,7 +4,7 @@
 
 register = template.Library()
 
-def oembed(input, args):
+def oembed(input, args=None):
     if args:
         width, height = args.lower().split('x')
         if not width and height: