Katy Perry sizzles in red Dolce & Gabbana at the premiere of 'Part of Me 3D'

7 of 11: Selena Gomez appears in a photo from Katy Perry's film premiere at Grauman's Chinese Theatre in Hollywood, California on June 26, 2012.

The concert film, 'Part of Me 3D,' premieres in theaters July 5. The documentary chronicles Perry's life on and off stage. (OTRC)