The Parklife hitmakers will take to the stage at London's Hyde Park on 12 August alongside supporting acts The Specials and New Order.
A post on the band's Facebook.com page, reads, "We're rowing in... going for gold... grabbing the baton... for the high jump... No, hang on, is that right?
"Fact is, Blur have accepted the invite to headline the Olympics' Closing Ceremony Celebration Concert in Hyde Park on 12th August."
The gig will be organised by BT London Live as part of a series of special events to mark the games coming to the capital.
The announcement comes just days after Blur guitarist Graham Coxon criticised London officials for agreeing to cut crowd capacity at Hyde Park and introduce a noise-reducing system after residents living nearby complained about the sound from gigs there.
Tickets for the BT London Live Closing Ceremony Celebration Concert go on Friday at 9am from www.btlondonlive.com.
Another concert is to take place in Hyde Park to mark the opening ceremony on July 27. There will be free performances at the venue on other dates during the Olympics.