Tickets are on sale at the Lollapalooza website: http://www.lollapalooza.com

Information from the official Lollapalooza site:
Take heed, Chicago: the Fame Monster herself is headed for your city, and she won’t leave ‘til she’s got your love. Lady Gaga and pop culture seem to go hand in hand these days, as the diva has enraptured fans with her extreme theatrics, her infectious music and her seemingly ever more outrageous outfits. Gaga’s debut album, The Fame, brought her the title’s promise, with hits destined to get bodies moving; “Just Dance,” “Poker Face,” “LoveGame” and “Paparazzi” introduced us all to her voice, and hinted at what has become her full-blown vision. They also earned her the elite status of being the only artist to have four No. 1’s from the same debut album on the Billboard Pop Songs chart. Since The Fame, Gaga has gone from alternate-universe, no-pants-Barbara-Streisand to human caricature, though no amount of strange objects in her hair or bizarro-clown makeup colors on her face can hide her talent as a brilliant pop songwriter. Perhaps Gaga is most endearing when she sits at her piano, her ivory-tickling skills and strong, soaring vocals on full display. Still, she seems most comfortable in full-out performance art mode, leading her backup dancers in evocative poses as disco balls spin and something, inevitably, ends up on fire. Citing Queen and David Bowie as huge influences, Lady Gaga has a penchant for exhibitionism, and in just a little over two years, has brought this fascination to mass audiences around the globe. Though she’s now a well-traveled sensation, back in 2007 Gaga wowed Lollapalooza attendees with an acclaimed Saturday performance. This year, a good guess suggests that on a bigger stage with a refined and greatly amplified production, she’ll blow everyone away.