You gotta hand it to Taylor Swift, she can definitely act too! (and keep herself from laughing better than Jimmy Fallon)

 

In this skit called 'Ew!', Taylor plays a nerd with braces and glasses who's not allowed to watch TV because of Miley Cyrus.  Meanwhile, Fallon plays the annoying (yet hilarious)  "Sara" (with no 'h', very important)