Rocker Eddie Vedder of Pearl Jam and the Oscar winner Sean Penn are a part of a documentary highlighting celebrity activism.

According to reports, Vedder and Penn performed as part of a show at a concert in California recently and their efforts were filmed for the new movie The People Speak. Vedder performed the classic folk song Here's to the state of Mississippi by Phil Ochs, changing lyrics to take aim at US president George Bush.

Other celebrities taking part included singer Jackson Browne, Chris and Rich Robinson of the Black Crowes and actor Don Cheadle. Celebrities who attended the bash included Diane Lane and Barbra Streisand.