Green Day are in the studio recording a new version of their hit single '21 Guns' with the cast of the musical 'American Idiot', the stage adaptation of their 2004 album.

The re-recorded version of the song is being produced by frontman Billie Joe Armstrong, and will be available for download on December 18th.

American Idiot premiered at Berkeley Rep on September 4th and was extended through to November 15th due to record-breaking sales and unprecedented demand for seats. Called "the hottest fall theatre ticket," by the San Jose Mercury News, American Idiot brought Green Day’s blockbuster album to life in a show staged by Tony Award-winning director Michael Mayer (Spring Awakening), who collaborated with Armstrong on the story.

Green Day recently announced a number of UK Arena shows for next summer, leading to speculation that they may headline Slane Castle in 2010. Fingers crossed....