A surprise appearance by Pearl Jam legend Eddie Vedder kicked off the Lollapalooza music festival on Friday when he appeared on stage with Ben Harper at Chicago's Grant Park.

The rock veteran was introduced by "special friend" Harper at the three-day American festival, before performing a special sit-down set with the ecstatic audience.

Texas-based symphonic rockers The Polyphonic Spree also wowed the crowd with a choral rendition of Nirvana's Lithium in a performance complete with tapdancers, while British band The Fratellis, M.I.A., The Rapture and LCD Soundsystem also took to the stage.

The first day of festivities was brought to a resounding close by French electronic duo Daft Punk, who shut the night down with an explosive act that included a psychedelic light show.

Lollapalooza will end on Sunday.

(This news article provided by World Entertainment News Network)