The clothes start to come off...
The "Jealous" singer packs a mean onstage presence.
The besties cheer on Calvin Harris while he performs on stage. Swift and Harris have sparked romance rumors but have not confirmed a relationship.
The hip-hop star performs on stage.
The American Idol alum gets a personalized BigTruck Brand hat before introducing a band onstage.
The singer sports a golden look on stage.
The singer cheers on Calvin Harris.
Before performing their hits including "Sledgehammer" and "Miss Movin' On," the girl group snacks on Sabra backstage.
The Property Brothers star gets super fierce at KIISFM's gifting suite.
The Keeping Up With the Kardashians momager is spotted in the audience watching Kanye West .
Before enjoying her favorite acts, the YouTube star does some serious shopping at KIISFM's gifting suite.
The singer and DJ performs on stage.
The glam rocker takes the stage.
Singers Lauren Jauregui, Ally Brooke, Dinah-Jane Hansen, Camila Cabello and Normani Kordei perform onstage.
The stars of KIIS-FM's On Air With Ryan Seacrest pose for pictures before introducing Nick Jonas and Justin Bieber.
The "Nobody Love" singer gets beautified with the help of Priv backstage.
The "All About That Bass" singer walks the red carpet.
NEXT GALLERY: More Singers Performing Live