Sigrid, Charlie Puth, Lord Huron and Tash Sultana are also among the artists on the bill this year.
"'ME!' is a song about embracing your individuality and owning it," Swift says.
Sam Smith will make his Billboard Music Awards debut to perform his collaborative hit single ‘Dancing With A Stranger’ with Normani.
This year's event featured jaw-dropping performance from Underwood, Swift, Cardi B, Panic! At The Disco and more.