 The span of nearly five years between "American Idiot" and "21st Century Breakdown" was the longest gap between studio albums in Green Day's career.The band had been working on new material since January 2006.By October 2007, Armstrong had 45 songs written, but the band showed no further signs of progress until October 2008, when two videos showing the band recording in the studio with producer Butch Vig were posted on YouTube.