Massive Attack and M.I.A. are to headline the Big Chill Festival in Herefordshire - which this year will see music-lovers encouraged to bare all.

Artist Spencer Tunick has been commissioned to create a new living masterpiece during the weekend - and is urging volunteers to take part in a mass disrobing.

On stage, R’n’B star Kelis will also join the festival, which will be held from August 5 to 8 against the backdrop of Eastnor Castle Deer Park, near Malvern.

Massive Attack, who after a seven-year gap have a new album titled Heligoland, will play the main stage on Friday night.

Saturday’s headline act, M.I.A. will take to the main stage while Kelis will perform on the second “tent” stage on the same day.

Grammy-nominated singer Bebel Gilberto is among the first of Sunday’s acts to be announced.

Off the stage, Tunick will create one of his “nude landscapes” - his first installation at a European music festival.

Volunteers will be instructed to arrive at a specific time and shed their clothing.

Participants’ nudity will be handled with “respect and sensitivity”, organisers said.

Tunick, whose work has been staged in Dublin, New York, Barcelona and at the Sydney Opera House, enlists ordinary members of the public in his projects, putting them at the heart of his artwork.

He said: “For me to be able to create one of my artworks in such a beautiful landscape is a real privilege.

“I’ve never carried out an installation at a European music festival before.

“I’m looking forward to doing a fantastical work, celebrating the body at play and interacting with such a unique setting.”

Tunick recently launched a recruitment drive for 1,000 volunteers to celebrate the 10th birthday of The Lowry, the gallery and arts venue in Salford’s former docks.

His latest collaboration is part of The Big Chill’s ongoing visual arts programme Art Trail.