Red Hot Chili Peppers will headline this year's Lollapalooza festival.

The 'Tell Me Baby' hitmakers will rock the three-day Chicago music event alongside a diverse range of bands including The Black Keys and Black Sabbath, who have also been confirmed as headliners.

Jane's Addiction frontman Perry Farrell - who founded the annual spectacle, which will take place in Grant Park from August 3 - was nervous about signing Black Sabbath after their summer preparations were rocked by health problems and they were forced to cancel a number of gigs.

He told Rolling Stone magazine: ''Every festival in the world wanted Black Sabbath to perform, but at the time of the announcement they had to back off and cancel all their shows.

''It broke my heart, but I just kind of kept a little fire building, a little kindling going to see if possibly we could get Black Sabbath. I didn't have much faith.''

Other acts confirmed for the event include Florence and the Machine, Bloc Party Jack White, Franz Ferdinand and Sigur Ros.