Mick Jagger may still be in his long-term relationship with the Rolling Stones, but the frontman has obviously had a wandering eye, and formed a new band on the sly.

Super Heavy is a combination of the singer, Joss Stone, Damian Marley, Dave Stewart and famed film music composer A.R. Rahman, The hodge-podge collective has been in and out of the studio for the last 18 months, reports Rolling Stone, and are plotting a full-length album for a September release.

"It's different from anything else I've ever been involved in," Jagger told the magazine. "The music is very wide-ranging – from reggae to ballads to Indian songs in Urdu."

"We didn't know what the hell we were doing," says Eurythmics co-founder and superstar producer Stewart on initially combining. "We were just jamming and making a noise. It was like when a band first starts up in your garage. Sometimes Damien would kick it off and then Joss would sing something on top of it. We might have a 22-minute jam, and it would become a six minute song."

He had gotten the idea for the combo listening to the noises around his house, in Jamaica."I live in Lime Hall right above St. Ann's Bay. It's kind of the jungle, and sometimes I'd hear three sound systems all playing different things. I always love that, along with Indian orchestras. I said to Mick, ‘How could we make a fusion?' We were talking about an experiment, and then we started talking about voices. It was all born from that conversation."

The group has no plans and has not decided yet if they will tour in support of the as-yet-untitled effort. Jagger refused to clarify if there were plans for the Stones to tour in the next year. "I don't have any announcement to make at the moment," he said. "I'm just, uh, ya know...just doing this right now."