How well does Katy Perry know herself? Judging by this video, not too well. lol

Lastnight on Jimmy Kimmel's show, Katy went head-to-head with a superfan and played a game of 'How well do you know Katy,' answering questions about well, herself. It seems that her biggest fan knew all there is to know about the singer. Or at least she was quicker and the answers popped in her head alot faster. Watch to see how it all went down and what cool prize her fan won:

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