Katy Perry Rocks American Idol 5/13/09 with Waking Up in Vegas (VIDEO)

Katy Perry took the stage on American Idol last night (5/13/09) singing 'Waking up in Vegas' live.

Katy Perry shows support for Adam Lambert

Katy got all Elvis'd up for fans last night on American Idol, wearing a hot Elvis inspired high-collared bodysuit and silk cape covered in shimmery rhinestones for her live performance of Waking up in Vegas. She also showed her support for who she wants to win this years competition - the cape she was wearing had Adam Lambert's name embroidered on it.

Check out the Katy Perry video from last night's American Idol and let us know what you think of her performance, and support for Adam Lambert, in the comments section below.

Katy Perry Waking Up In Vegas Video