Guest Stars Selena Gomez as Herself Chadwick Boseman as Himself BTS as Themselves Christina Aguilera as Herself Bebe Rexha as Herself watt as Himself Zedd as Himself Khalid as Himself Hailee Steinfeld as Herself Demi Lovato as Themselves Kelly Clarkson as Herself Pink 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