LOS ANGELES — Mariah Carey is set to perform on the Billboard Music Awards for the first time in 17 years, but the pop superstar is keeping mum on what song she she'll sing. Billboard and Dick Clark productions announced Tuesday that Carey will appear on the May 17 show in Las Vegas. Billboard says the singer has more No. 1 songs on its Hot 100 chart than any other solo artist in the chart's 56-year history. Previously announced performers include Kelly Clarkson, Sam Smith, Ed Sheeran, Van Halen, Britney Spears and Iggy Azalea. Presenters include Rita Ora, Ne-Yo, Laverne Cox and the cast of “Entourage” — Kevin Connolly, Kevin Dillon, Jerry Ferrara and Adrian Grenier. — AP