They'll headline the British Summer Time festival on 20 June.
The band, who got back together for a pair of reunion shows in the park six years ago, join Taylor Swift, Kylie and The Who on the bill.
Speaking at a news conference in a London Chinatown restaurant, frontman Damon Albarn joked: "I love it because I can cycle to work".
They'll be the only band ever to play Hyde Park four times after this performance.
Bassist Alex James says that "since we made our last record as a four-piece we have probably only done 20 gigs.
"So for me every time we play together it feels special but in order to keep doing it we need something news to do."
Blur are also working on their first studio album as four-piece in 16 years, The Magic Whip.
Guitarist Graham Coxon said they started recording in Hong Kong when a gig was cancelled.
He said: "we thought we'd put a few days, five or six days, to good use".
The album is influenced by the band's time in Far East.
Damon Albarn confirmed one song was about time he spent in North Korea: "it's my impression of the place, in a very abstract veiled way.
"When you listen to it is pretty self explanatory what it's about".
The singer also said it was nice to work with a basic set-up when they first started to make the album to see what they could create.
He told the news conference that "we didn't have much stuff so it was like recording when we first started doing stuff.  It was a really small studio, it was really hot and claustrophobic.
"We just went in there and knocked about some ideas."
The album will be released on 27 April.
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Blur are heading back to Hyde Park with their first album in more than a decade.