Pharrell Williams (left) and Camila Cabello perform during the 2018 Billboard Music Awards.Janet Jackson performed on TV for the first time in nine-years at the 2018 Billboard Music Award.Recording artists Andrew Taggart and Alex Pall of music group The Chainsmokers accept the Top Dance/Electronic Artist award.Recording artists Khalid and Normani perform onstage during the 2018 Billboard Music Awards at MGM Grand Garden ArenaAriana Grande's Topsy-Turvy Billboard Music Awards Performance.Christina Aguilera and Demi Lovato perform onstage during the 2018 Billboard Music Awards.