The band last appeared at the Worthy Farm event in 2009, and were one of the acts rumoured to replace Foo Fighters as the headliner, reported Digital Spy.
Band member Alex James said, "We did Glastonbury in 2009, I think that was one of the best gigs we have ever done. I think you can only do Glastonbury once a decade.
"We are really looking forward to playing around the world. We don't want to overdo it."
Florence + the Machine were confirmed to headline on June 26 after Foo Fighters' Dave Grohl broke his leg on stage during a recent show.
Blur's comeback album "The Magic Whip" topped the UK Albums Chart back in April.