Later she attended the film's premiere wearing a long, shiny silver dress. The red carpet was decorated with giant lollipops and a huge image of the pop star next to her guitar.
The film takes fans behind the scenes of her "California Dreams" tour.
Katy has been showing off a lot of skin lately. Over the weekend she hung out at a Miami hotel in various bikinis. She has also reportedly been hooking up with singer John Mayer. She just recently finalized her divorce from British actor Russell Brand.
See more photos of Katy...