The two-day event will take place on June 23 and 24 on Hackney Marshes in East London and mark the run-up to the London 2012 Olympics.
It will be the biggest free-ticketed event that Radio 1 has ever organised, with 100,000 people able to attend over the weekend. The majority of the tickets will be distributed among people living locally and in neighbouring boroughs.
The music event will have six stages including the Radio 1 Main Stage, the 1Xtra Arena - which will hold 30,000 people - the In New Music We Trust stage and the BBC Introducing stage.
Over 80 acts will be playing the stages across the weekend, making it the largest multi-act lineup that Radio 1 has ever organised.
The festival will be broadcast on BBC Three, with additional buildup programming due to be unveiled in the coming months.
The event will mark the opening weekend of the London 2012 Festival.
Earlier this month, Foo Fighters, Lady GaGa and the Black Eyed Peas played Radio 1's Big Weekend in Carlisle.
Watch Leona Lewis perform at the closing ceremony of the 2008 Beijing Olympics below: