U2's Bono and The Edge.

U2 and Green Day have joined forces to record a charity song, and will unveil it during a live performance in New Orleans on September 25, Billboard.com reports.

The track, a cover of Scottish punk band The Skids' "The Saints Are Coming," will serve as the official reopening of the Louisiana Superdome prior to a New Orleans Saints' football game.

The Superdome was almost destroyed in the aftermath of Hurricane Katrina when it was used as a shelter by thousands of displaced people.

Proceeds from the release of "The Saints Are Coming" will go to Music Rising, an initiative co-founded by U2 guitarist The Edge which helps musicians who lost their instruments during Hurricane Katrina.

U2 have already recorded their parts for "The Saints Are Coming," and Green Day are in the middle of their work for the track. (Watch U2 and Green Day channel the Beatles in a photo shoot for the song here.)

U2 are also in the early stages of recording the follow-up to 2004's "How to Dismantle and Atomic Bomb," which is being produced by heavyweight knob turner Rick Rubin.

In an online diary on the band's official website, one new track was said to be "a U2 classic with an instant hook and a mesmerizing chorus."

No release date has been announced for the album.