The "Skyscraper" songbird, who is joining the Fox singing competition for its second season, will also host the Teen Choice Awards on Fox.
Fox also announced Monday that Cat Deeley, host of its dating show "The Chocie," has been added to the list of Teen Choice talent.
Justin Bieber, Carly Rae Jepsen, Flo Rida and No Doubt are performing. "Jersey Shore" star DJ Pauly D will DJ. And Miley Cyrus, Zooey Deschanel, Ellen DeGeneres and Zac Efron are among the previously announced talent.
"Teen Choice 2012" will air live July 22. Fans can vote for at the ceremony's web site until 11:59 p.m. the previous night.
Lovato, who is currently touring the U.S., will premiere as an "X Factor" judge, along with fellow new addition Britney Spears, when the show returns on Wednesday, Sept. 12.
