Katy Perry & Amber Heard Head Back To The '90s For Friend's Roller Party! (PHOTOS)

Rachel Bilson and Hayden Christensen attend Johnny Wujek's Rollerskating Birthday Party at MoonLight Rollerway in Los Angeles. Photo Credit: WENN.com/The Cobra Snake

Katy, Nicki & Gaga are the Queens at Rocking the Most Hazardous Costumes! (PHOTOS)