Katy Perry and Kanye West performed their hit collaboration "E.T." on Thursday noght's episode of "American Idol."  Watch a clip of the performance below.  "E.T." was the fourth single from Perry's "Teenage Dream" album, and was released February 16th, 2011.  The song is the last song to sit atop both the Billboard Hot 100 and Billboard Dance Club Play Charts at the same time.