Jessie J, Professor Green and Ed Sheeran are among the acts added to the bill of the Radio 1's Olympic event, Hackney Weekend.
The event - also featuring Lana Del Rey and Jack White - is expected to be attended by 100,000 people across two days in June.
Already announced for the station's biggest ever free show, taking place at east London's Hackney Marshes, are acts including Tinie Tempah and Plan B.
More than 100 artists will play on six stages as part of the BBC's Olympic celebrations.
N-Dubz star Dappy and Brits Critics' Choice winner Emeli Sande were also among the latest additions announced by breakfast show host Chris Moyles this morning.
Fans can register an interest in tickets from Monday, with applications taking place in March. The majority of tickets are being reserved for people from Hackney and nearby Olympic boroughs.
The event is being staged on June 23 and 24 and will also be screened on BBC3.
Event director Jason Carter said: "This event will be a massive celebration in such a special year for us all."
Professor Green said: "Hackney is a great place, so events like this and the Olympics will help showcase the borough in a positive light."