Major stars such as Rihanna, Jay-Z and Jack White are preparing to play the BBC's biggest ever free live music event, Radio 1's Hackney Weekend.
Around 100,000 people are expected to flock to east London to attend the festival, part of the BBC's Olympic celebrations, with more than 100 acts taking to six stages.
In excess of 250,000 people applied for tickets for the event at Hackney Marshes, with most reserved for people from the neighbouring Olympic boroughs.
Hip hop star Jay-Z is topping the bill for Saturday's show, while Rihanna is the biggest headliner on Sunday.
Other big names appearing over the two-day festival include Jessie J, Ed Sheeran, Tinie Tempah and Florence + The Machine.
Black Eyed Peas star Will.i.am is also on the bill, along with Leona Lewis and Plan B. There have been reports that Cheryl Cole may perform.
Organisers have been working closely with police to ensure safety at the show, part of the London 2012 Festival which kicked off this week.
The site is surrounded by two rings of security barriers, one of which is 12ft (3.7m) high and more than 1,200 security staff will be on hand.
The event is more than twice the size of the radio station's Big Weekend event and has been two years in the planning.
Hackney Weekend - taking place over the weekend usually occupied by Glastonbury Festival, which is resting this year - is being broadcast by Radio 1 and will also be screened on BBC Three.