Enter his instantly iconic and subdued (for him, at least) cover of the unsettling song. Lambert opted for the slowed-down Gary Jules and Michael Andrews version of the tune -- as featured on 2001's Donnie Darko soundtrack -- as opposed to the 1982 synth-pop original, sprinkling the somber song with some unexpected note choices, especially his ending wail. The buzzy performance helped carry Lambert all the way to the finale, where he finished in the runner-up slot to Kris Allen, and Adam has found success as a solo singer as well as touring with Queen in the decade-plus since.
For Clarkson's new take, she borrows a bit from both versions, opting for the slower tempo of the newer cover but adding some heavy drums and guitars at the end that recall the peppier original. Clarkson, of course, won the very first season of American Idol in 2002, launching her blockbuster music career and leading to the full-circle Kellyoke covers she performs each day on her talk show almost 20 years later.
"Mad World" never charted for Tears for Fears, but the Jules and Andrews cover became a radio hit, topping the Adult Alternative Airplay chart in 2004.
Watch Clarkson and Lambert's covers of "Mad World" below: