Black Sabbath will headline this year's Lollapalooza festival in Chicago, marking their only North American gig of 2012. The band was reportedly tapped to headline Coachella at one point, but had to pull out when Tony Iommi was diagnosed with lymphoma.

Even Lollapalooza founder Perry Farrell was doubtful that Sabbath would be able to join the fest, which will take place on August 3-5. "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," Farrell tells Rolling Stone from São Paulo, Brasil, where the Jane's Addicition frontman was on hand to debut the South American country's first-ever installment of Lollapalooza last weekend. "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."

With Iommi having recently completed his chemotherapy, Sabbath manager (and frontman Ozzy Osbourne's wife) Sharon Osbourne reached out to Lollapalooza organizers to accept their offer. "They mean so much to me, and they mean so much to music in general, that I kind of feel like I'm dreaming to know that Black Sabbath is actually gonna perform at Lollapalooza," says Farrell.

Joining Sabbath on the Lolla lineup is a cavalcade of color-named bands, including the Red Hot Chili Peppers, Jack White and the Black Keys. Rounding out the bill are the reunited At the Drive-In, Florence and the Machine, Miike Snow, Bloc Party, Franz Ferdinand, Delta Spirit, Metric, Gaslight Anthem, Sigur Rós, the Shins, Kaskade, Bassnectar, J. Cole, Childish Gambino, and another big reunion in the Afghan Whigs. As of now, the Whigs' Lolla gig is their first U.S. reunion show; the band is slated for an already-announced apperance at All Tomorrow's Parties in New Jersey this September, Rolling Stone reported.