Blur will perform as a four-piece for the first time in nine years next summer, at a huge concert in Hyde Park.
The full line-up - Damon Albarn, Graham Coxon, Alex James and Dave Rowntree - will take to the stage in the capital in July for their first performance since 2000.
Coxon quit the band in 2002 but he and Albarn have put their differences behind them to confirm the massive summer concert.
"It just felt it was right again," Albarn told NME.
"It somehow feels like there's something for us to do again, we're not completely useless or pointless, we've got a reason to exist."
Coxon added the band were "making public what's been going on a little bit privately".
"For the benefit of the fans and those interested we can say that something's on the cards".
The announcement has fuelled speculation that the band will embark on a tour while a headlining spot at next year's Glastonbury Festival is also rumoured.
Speaking to the BBC, a spokesman for the Somerset event said the line-up was far from finalised.
"We are talking to headliners at the moment," he said.
"There is lots of speculation about who might or might not be playing next year. We're confident it will be as good as Jay-Z. No headliners have been confirmed."
However, Albarn admitted the band were certain to announce more reunion shows for 2009.
"We'll do something in London because that seems sensible," he said, "but we're also playing in other parts of the country working up to there."
Tickets for the July 3rd Hyde Park concert - which cost £45 - go on sale at 09:00 GMT on Friday December 12th.