Maroon 5, with lead singer Adam Levine, rock the stage on NBC's "Today" at Rockefeller Center in New York City on Friday.

Dave Ritter and Jimmy Chauveau of The Strumbellas talk to Q's Tom Power about keeping an act alive when the frontman changes. Their brand new album, Part Time Believer, is out now.

A-ha lead singer Morten Harket is seen performing at the Rock in Rio Music Festival in Rio de Janeiro in 2015. The front man of the Norwegian synth-pop band has Parkinson's disease.