The act – best known for singles including A Design for Life and If You Tolerate This Your Children Will Be Next – formed in the Welsh mining town of Blackwood in 1986 and went on to become one of the biggest and most influential bands of the 1990s.
They have headlined numerous festivals including Glastonbury, and T in the Park, and have won 11 NME Awards, eight Q Awards and four BRIT Awards.
The trio are now recording their 14th studio album.
Daniel Matthews, co-director of Electric Park, said: ‘We’re so thrilled to be able to announce the unbelievably exciting news that the festival will now be headlined by Manic Street Preachers.
‘The title “rock gods” is bandied about quite freely nowadays but it’s fair to say that it’s a title that applies to the Manics.
‘They’ve headlined Glastonbury, won award after award, put out one incredible album after another over the past 30 years and they’re quite simply going to blow the Electric Park audience away.
‘It’s been a tough year for live-music fans so I hope today’s announcement gives people a reason to start looking forward to a brighter 2021.’
The organisers have previously confirmed that Razorlight and US rock band Dr Hook, who were both due to appear at this summer’s cancelled event, will be performing at next year’s festival in the People’s Park on 10 July.