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. "Subscribe To ""The Late Late Show"" Channel HERE: http://bit.ly/CordenYouTube Watch Full Episodes of ""The Late Late Show"" HERE: http://bit.ly/1ENyPw4 Like ""The Late Late Show"" on Facebook HERE: http://on.fb.me/19PIHLC Follow ""The Late Late Show"" on Twitter HERE: http://bit.ly/1Iv0q6k Follow ""The Late Late Show"" on Google+ HERE: http://bit.ly/1N8a4OU Watch The Late Late Show with James Corden weeknights at 12:35 AM ET/11:35 PM CT. Only on CBS. Get the CBS app for iPhone & iPad! Click HERE: http://bit.ly/12rLxge Get new episodes of shows you love across devices the next day, stream live TV, and watch full seasons of CBS fan favorites anytime, anywhere with CBS All Access. Try it free! http://bit.ly/1OQA29B --- Each week night, THE LATE LATE SHOW with JAMES CORDEN throws the ultimate late night after party with a mix of celebrity guests, edgy musical acts, games and sketches. Corden differentiates his show by offering viewers a peek behind-the-scenes into the green room, bringing all of his guests out at once and lending his musical and acting talents to various sketches. Additionally, bandleader Reggie Watts and the house band provide original, improvised music throughout the show. Since Corden took the reigns as host in March 2015, he has quickly become known for generating buzzworthy viral videos, such as Carpool Karaoke."