The headlining acts for this year's Lollapalooza festival have finally been revealed and the organisers have secured some of the best acts out there. 

2011 marks the 20th anniversary of the event, which will take over Chicago's Grant Park from August 5-7, and heading the bill will be four incredibly diverse but internationally acclaimed stars Coldplay, Muse, Eminem and Foo Fighters. 

In addition to this fantastic announcement, other bands and artists have been confirmed for Lollapalooza including BRIT award-winning Tinie Tempah, soul maestro Cee Lo Green, Lykke Li and deadmau5. 

Watch Chris Martin of Coldplay performing at 2010's Apple music event here: