Coming Soon: Tenacious D's Big Fat Movie

Still-untitled flick will detail 'how Tenacious D became the greatest band on Earth.'

They've rocked your stereo, they've rocked your TV, and now the self-proclaimed "greatest band on earth" plans to rock the big screen.

The comedy duo of Jack Black and Kyle Gass, a.k.a. "The D," have signed on to star in the first Tenacious D silver screen adventure, to be directed and co-written by "Sifl & Olly" co-creator Liam Lynch, according to a New Line Films spokesperson.

In addition to co-writing the script with Lynch, Black and Gass will produce the still-untitled movie. The film will be "a creation story based on how Tenacious D became the greatest band on Earth," according to the D's Web site.

A New Line production president told the Hollywood Reporter that he sees the film as falling somewhere between the Beatles' "A Hard Day's Night" and the metal spoof "This Is Spinal Tap."

Black and Gass first hooked up in Los Angeles in 1994, making their somewhat unfortunate movie debut in the 1996 clunker "Bio-Dome." They scored slots on the HBO series "Mr. Show With Bob and David," landing their own short-lived series on the channel in 1999.

Tenacious D dropped their self-titled recorded debut in 2001, featuring contributions from Foo Fighters' Dave Grohl and Phish's Page McConnell. Black, meanwhile, earned his stripes acting in movies such as "Jesus' Son," "The Cable Guy," "High Fidelity" and his headlining debut, "Shallow Hal." Gass has appeared in the films "Jacob's Ladder" and "Evolution."

Though the Tenacious D film isn't expected to hit theaters before next year, Black can be seen in the upcoming music comedy "The School of Rock," directed by Richard Linklater ("Waking Life," "Slacker") and written by Mike White ("Chuck & Buck," "The Good Girl").

Joan Cusack and comedian Sarah Silverman co-star in the story of a down-on-his-luck musician (Black) who takes a job as a fourth grade substitute teacher after being fired from his band. In an effort to raise money, he forms a group with his students to compete in a battle of the bands.