Bastille, Bombay Bicycle Club, Wolf Alice and the Chemical Brothers have been named as the musical headliners for Latitude Festival.
The four-day event is due to be held at Henham Park in Suffolk in July.
Comedians Bill Bailey, Katherine Ryan and Jo Brand will also appear at the event, which was cancelled last year.
Organiser Melvin Benn said he has “confidence” the festival would go ahead as planned, with limits on social contact due to be removed on 21 June.
The date is the final point on the government’s roadmap out of lockdown.
Mr Benn said in March the event would run at full capacity – with 40,000 people on site – with negative Covid tests a requirement of entry.
Earlier this month 5,000 people attended an event to test Covid-19 transmission at Liverpool’s Sefton Park, which Mr Benn produced.
That trial event and others held in Liverpool did not cause any detectable spread of the virus, the city’s health chief said.
Mr Benn said: “I believe it was a massive success and demonstrated there is a way to produce festivals in a Covid-safe manner.”
Brit Award winners Bastille will headline the main stage on Sunday.
Dan Smith, from the band, said: “We’ve wanted to play and go to Latitude for such a long time, so we’re really excited to have the chance to be there after everyone’s year away from gigs.”
Bastille are the only act from a trio announced for this year’s event back in July to remain on the bill.
Lewis Capaldi went on to postpone all of this year’s gigs, and Snow Patrol are no longer on the line-up – neither are First Aid Kit, who were previously added.
But Dry Cleaning, Griff, Arlo Parks, Fontaines D.C, Rudimental, Kaiser Chiefs and Mabel are due to play at the festival, which runs from 22 to 25 July.
Charlie Mackesy, author of the book The Boy, the Mole, the Fox and the Horse, will also perform at the event, which has always described itself as “more than a music festival”.
The cartoonist, who lives in Suffolk, said Latitude “has always felt free, and open and kind, and it seems to transcend the ages.
“It never crossed my mind that one day I would actually be performing.”