It’s official. Lady Gaga, as was reported in February initially, will be making her headlining debut this summer at Lollapalooza.

Green Day, along with a reunited Soundgarden, will be joining the pop singer as headliners for the 2010 edition of the long running festival. It will take place at Grant Park in Chicago August 6-8.

Lady Gaga had one previous appearance at the festival in 2007 on one of the smaller side stages.

Other acts that the organizers have confirmed for the outdoor festival of three days include Grizzly Bear, Erykah Badu, The New Pornographers, Spoon, The Black Keys, Hot Chip, MGMT, Phoenix, The Strokes and Arcade Fire. Lollapalooza’s website contains a complete listing of performers.

The festival’s headlining lineup for 2010 skews toward edgier and younger than last year’s top performers. They included veteran acts Lou Reed, Jane’s Addiction, Tool and Depeche Mode. It will be the second appearance at Lollapalooza for Green Day. The first appearance for the band was in 1994. At that time, the festival was a traveling show featuring dates across the country. Soundgarden, reuniting after 12 years, appeared at Lollapalooza previous in 1992 and 1996.

Jane’s Addiction, which is led by Perry Farrell co-founder of Lollapalooza, isn’t appearing at the event this year. However Ferrell will be performing a set as DJ at the electronica stage named after him at the festival. Other electronic acts for 2010 include Felix Da Housecat, Digitalism, Empire of the Sun and 2ManyDJs.

Festival tickets are on sale currently. Three day general admission passes cost $215. VIP passes cost $850. The event’s website also has travel packages available.