Though it had been rumored in the days leading up to the Reading Festival, Green Day's surprise set didn't become reality until Billie Joe Armstrong took to Twitter about 45 minutes before the set to announce where they were playing.

NME reports that the announcement sent fans into a frenzy, so much so that organizers were forced to seal off access to the stage, leaving a good portion of the crowd left outside the main staging area to catch the show on a big screen.

The group had been rumored to be playing the 'Dookie' album in full earlier in the week, but fans were treated to five tracks from the band's breakout album, including 'Welcome to Paradise,' 'Burnout,' 'Longview,' 'Basket Case,' and set closer 'She.'

Though the band has been pretty open with new material at recent stops, they chose to only offer up 'Stay the Night' from their forthcoming album trilogy during the set. However, they did dig deeper into the past to pull out such favorite album tracks as 'Murder City,' 'Letterbomb' and 'St. Jimmy,'

Perhaps due to the last minute nature of the performance, there was a little drama between the band and festival organizers when they were asked to start wrapping up the show. Singer Billie Joe Armstrong told the audience, "We're having a little f---ing problem with time," as the band played a curtailed version of 'Boulevard of Broken Dreams.' But while revealing what was happening, Armstrong didn't bow to pressure and kept right on rocking.

'¡Uno!,' the first part of the band's trilogy, is due Sept. 25. In related news, the band's appearance in the new 'Angry Birds Friends' game has gone live here.

Watch Green Day's 'Welcome to Paradise' from the Reading Festival
Green Day Aug. 24 Reading Festival Set List:

'Welcome to Paradise'
'Murder City'
'Stay the Night'
'Burnout'
'Hitchin' a Ride'
'Letterbomb'
'Brain Stew'
'St. Jimmy'
'Longview'
'Basket Case'
'American Idiot'
'Minority'
'She'