Spoof rock band Spinal Tap will reform to play the Live Earth concert at Wembley Stadium in London in July.
Spinal Tap are releasing a new single, Warmer Than Hell
The group, who were created for Rob Reiner's cult 1984 film This Is Spinal Tap, have been added to a bill that also includes Madonna and Genesis.
Reiner joked that Christopher Guest, who played guitarist Nigel Tufnel, thought global warming meant he was "wearing too much clothing".
Seven shows will take place around the world to highlight climate change.
The other concerts will be held in New Jersey, Sydney, Tokyo, Rio de Janeiro, Johannesburg and Shanghai.
Spinal Tap will share the London bill with acts including James Blunt, the Red Hot Chili Peppers, Snow Patrol and Duran Duran on 7 July.
Rob Reiner has directed a new short film on the band's reunion
The group, who have reunited several times since the film, are also releasing a new single called Warmer Than Hell.
Reiner, 60, has worked with environmental group the National Resources Defense Council for more than 20 years and is hoping the message will have a substantial effect.
He has also directed a new 15-minute film about the band's reunion, which will be shown at the opening night of the Tribeca Film Festival in New York on Wednesday.