Guest Stars Selena Gomez as Herself Christina Aguilera as Herself BTS as Themselves Chadwick Boseman as Himself Bebe Rexha as Herself watt as Himself Zedd as Himself Khalid as Himself Hailee Steinfeld as Herself Demi Lovato as Themselves Pink as Herself Kelly Clarkson as Herself Diana Ross as Herself Niall Horan as Himself Alesso as Himself Alessia Cara as Herself Imagine Dragons as Themselves Portugal. The Man as Themselves Florida Georgia Line as Florida Georgia Line