Former US President Bill Clinton is to tread the boards with the Rolling Stones to help raise awareness about global warming.
Clinton is due to appear with the veteran rockers at a free concert on Thursday at the Staples Centre in Los Angeles.
But the saxophone-playing former US president was not expected to play with the band. Instead he will make a speech about the importance of fighting global warming, concert organisers said.
About 12,000 fans won tickets to the show in an Internet draw last month. Other received passes through radio station promotions.
The band is currently completing the North American stretch of its Forty Licks World Tour and will kick off the international leg later this month in Australia.