Do you know Katy Perry better than, well, Katy Perry?  Jimmy Kimmel puts one super-fan to the test. In a rousing game of "Who Knows Katy?", Perry-cultist Emily proves her devotion by knowing Katy's Grammy's record better than the singer herself.

The Candy Queen also took some time to promote her latest single, "Birthday", for which she shared some hallucinatory teasers.

Check out the game and interview, below!

h/t: OhNoTheyDidn't