"If the little kid who grew up in Tennessee could see me now, he would be so proud," Hightower told host Terry Crews.
"I think your name is gonna be on the lips of everybody watching this across the globe." judge Howie Mandel told the singer.
"It was actually magic. One of my favorite ever acts," Cowell tells the troupe backstage.
“You are somebody who has a God-given talent. And it’s rare," Simon Cowell told the young star.
StemDrop will give TikTok's more than 1 billion monthly users the chance to create their own songs using music "stems" from an exclusive new track written by Max Martin, Savan Kotecha and Ali Payami.
The band also shared their new single “H2L” from the remaining members.
