The catchy hitmakers posed together at the Los Angeles premiere of Katy Perry: Part of Me and the kick off for the Pepsi/Billboard Summer Beats Concert Series. On seeing the ups and downs of the movie, Perry is all about focusing on the ups: "It’s not always nice to see myself looking awful, but sometimes you have to get through the curveballs in order to achieve your dreams," Katy Perry told reporters. The film opens July 5th. Click through the gallery to see Emma Stone, Selena Gomez and more stars at last night's hottest parties.
—Leah Abrahams, with reporting by Brooke Mazurek and Lindzi Scharf