Demi Lovato and James Corden have a Divas Riff-Off

Were original divas better than ones today? That's what this Late Late Show Riff-Off is about! 

When Demi Lovato takes exception to James Corden's claim that divas such as Cher, Aretha and Tina Turner are more fierce than today's divas, and the two decide to settle it in a Riff-Off featuring songs from Adele and Katy Perry, with some backing vocals from Level.