Green Day surprised fans at the Reading Festival today (August 25) by performing a secret show.

There had been word during the week of the US punk trio performing the event, with it being mooted that the band would play their seminal 1994 album 'Dookie' in full.

Frontman Bille Joe Armstrong confirmed their slot on Twitter this morning, tweeting:

"Green day - READING FESTIVAL CONFIRMED!! On stage in 45 minutes! In the NME / RADIO 1 tent. 11am!! Be there!."

The band didn't play 'Dookie' start to finish, however, as they ran through what turned out to be a largely greatest hits set of their older material.

They took to NME/Radio 1 tent - a smaller venue than their natural main stage home.

Twitter soon become ablaze with talk of the show, with one user tweeting:

"Green day were awesome! Worked on the bar right in front of them!"