Miley Cyrus, Olympic swimmer Michael Phelps and singer Ciara will also present awards, the network confirmed.
High School Musical stars Zac Efron, Vanessa Hudgens, Ashley Tisdale and Corbin Bleu will also do the honours, alongside Kristen Stewart, Robert Pattinson and Taylor Lautner from upcoming movie Twilight.
The Ting Tings, Katy Perry, T-Pain and Lupe Fiasco will perform hits from the last 25 years to mark the event's quarter century.
Pink, Rihanna, Paramore, TI, the Jonas Brothers, Lil Wayne and Kid Rock were previously confirmed for the lineup.
The ceremony, to be hosted by Russell Brand, will be held in Los Angeles on September 7.
Britney Spears's manager recently denied rumours that the singer will perform at the awards.