Gnarls Barkley was formed in 2002 by Danger Mouse and CeeLo Green, who met while working on various music projects. The duo gained initial recognition with their debut single "Smiley Faces," which was featured on the soundtrack for the film ATL . However, it was their follow-up single "Crazy" that catapulted them to international fame. Released in 2006, "Crazy" became a massive hit, topping charts worldwide and earning a Grammy nomination for Record of the Year.