Demi Lovato [1] is a diva and now the world knows it. The singer challenged James Corden to a Divas Riff-Off, and boy did she give him a run for his money. While James sang some older classics like Aretha Franklin's "Respect," Demi brought it back to this generation with Adele's "Rolling in the Deep" [2] and her own hit "Heart Attack." The two proved to be very tough competitors but only one reigned supreme. Watch the video above and see for yourself.
