Watch Katy’s crew prepare the ExtraTerrestrial costumes and dance choreography for her upcoming performance of “ET” on American Idol THIS THURSDAY, 4/21! Check out the official “ET” music video, featuring Kanye West, here: goo.gl Watch Katy Perry perform “ET” on American Idol this Thursday, April 21 at 8/7c on Fox. Get “ET” featuring Kanye West on iTunes here: goo.gl