Just found this on a Green Day page (http://www.geocities.com/SunsetStrip/Alley/4619/kingofthehill.html). Haven't seen mention of it here, so ...
Green Day To Appear On Fox's "King Of The Hill" Cartoon
The three garage-band graduates who comprise Green Day took a break from recording their new album with Rob Cavallo last Wednesday (May 21) to venture down to the Fox Studios in Burbank to record voiceovers for a next-season episode of King Of The Hill, the "adult-oriented" animated comedy from the creator of Beavis And Butt-head that has prospered in its cushy "hammock" between Fox's two biggest hits, The Simpsons and The X-Files, to become a ratings success.
Unlike most celebrity "guest shots" on cartoon series, the Green Day gang won't be portraying animated versions of themselves instead,they'll supply the voices of a noisy garage band that disturbs the neighbors in Hank Hill's neighborhood. Quite a stretch for the fellas, but they're excited because KOTH is one of their favorite shows unlike Stone Temple Pilots, who we hear turned down a similar guesting opportunity.
The band will play an annoying garage band called Cane & the Subborn Stains, which features, in a playful switch- around, drummer Tre Cool on vocals and guitar as Cane, singer/ guitarist Billie Joe Armstrong as Face, the bass player, and bassist Mike Dirnt as Zeus, the drummer. In the episode, titled "The Man Who Shot Cane Skretteburg," the show's lead character Hank Hill gets into a paint- gun war with Cane, the lead singer of the band.