Jack Black poked fun at critics of Tenacious D's headlining set at San Francisco's Outside Lands festival on Sunday (30Aug09) - with a quirky T-shirt. Black and bandmate Kyle Gass were last-minute replacements for the Beastie Boys, who pulled out when Adam Yauch was diagnosed with cancer, prompting many to suggest they weren't a good enough stand-in. The duo decided to address the issue by offering souvenir T-shirts depicting the Beastie Boys’ Check Your Head album cover with Black and Gass photoshopped in. The title read Check Your Headliner.