Justin Timberlake Dares Jimmy Fallon to Take the ALS Ice Bucket Challenge

Douglas Gorenstein/NBC
Dave Guy, Horatio Sanz, Damon "Tuba Gooding Jr." Bryson, Ian Hendrickson-Smith, Rob Riggle, Ahmir "Questlove" Thompson, Mark Kelley, host Jimmy Fallon, announcer Steve Higgins, James Poyser, James "Kamal" Gray, Tariq "Black Thought" Trotter, Frank "Knuckles" Walker and Kirk "Captain Kirk" Douglas participate in the "Ice Bucket Challenge" on August 12, 2014 on the Tonight Show.

What goes around, goes around, goes around...

Tuesday night on the Tonight Show, via video, Justin Timberlake challenged Jimmy Fallon and The Roots to take the ALS Ice Bucket Challange, where you dare someone to dump a bucket of freezing cold water on themselves within 24 hours. If they refuse, they have to donate money to fight ALS (otherwise known as Lou Gehrig's disease). Fallon shared he'd be donating money, but -- thanks to the enthusiastic support of the studio audience -- The Roots, Steve Higgins, guest Rob Riggle, Horatio Sanz and Fallon himself would also be dumping ice water on themselves.

Watch the challenge below, and find out who Fallon has passed the dare to: