I must have missed this announcement...from Wiki:

Super Heavy is a rock supergroup consisting of Rolling Stones lead vocalist Mick Jagger, Dave Stewart, Joss Stone, Damian Marley, and A.R. Rahman. Stone and Stewart had collaborated in the past with Jagger. The band's formation was announced on 20 May 2011. Jagger said of the band, "We wanted a convergence of different musical styles... We were always overlapping styles, but they were nevertheless separate".

Album is out in September (supposedly).

[Edited 6/15/11 13:52pm]