Mick Jagger is branching out musically by forming a new supergroup with Eurythmics guitarist Dave Stewart, reggae singer Damien Marley, soul siren Joss Stone and Indian music composer A.R. Rahman.

The outfit, called Superheavy, was conceived via a phone call between the Rolling Stones singer and Stewart in which they discussed new ways in which they could collaborate. "We wanted a convergence of different musical styles," Jagger tells Rolling Stone magazine. The two previously collaborated by writing music together for the soundtrack to the 2004 film 'Alfie.'

In order to get the sounds they wanted, the pair recruited an eclectic lineup that includes the aforementioned Marley, Stone and Rahman, who each represent a different musical genre. "It's different from anything else I've ever been involved in," says Jagger. "The music is very wide-ranging – from reggae to ballads to Indian songs in Urdu."

Over the last year and a half, the group has been hard at work on their debut album, with hopes to release it in September. "One of the beauties is that, just speaking as a vocalist, I did other things," reveals Jagger of the recording sessions. "I played guitar and harmonica, but there's four vocalists on the album. Not everything was reliant on me.”

Superheavy, whose name came out of some impromptu vocalizing by Marley, have no plans to tour yet. However, Stewart says that 'nobody would rule out the possibility' of playing some live shows.

Jagger, meanwhile, thinks Stones fans will dig the disc. "It is a different kind of record that what people would expect," he explains. "It's not all weird and strange though. I think Stones fans will think it's a bit odd, but they'll find most of it accessible."

Watch a Clip of Mick Jagger and Dave Stewart Performing 'Party Doll' in 1987