Iggy Azalea, Florida Georgia Line, Jason Aldean and Meghan Trainor will also hit the stage on March 29 at the Shrine Auditorium in Los Angeles, iHeartMedia announced Monday. Jamie Foxx will host the awards show.
Azalea and Smith are the top nominees, with five nominations apiece. Azalea, Smith, Taylor Swift, Ariana Grande and Luke Bryan are nominated for artist of the year.
Swift will make an appearance, while other performers include Kelly Clarkson, Snoop Dogg, Jason Derulo, Jennifer Hudson, Alesso and Nate Ruess of fun.
The three-hour event will air live on NBC and iHeartMedia's radio stations.