Sum 41 have begun work on the follow-up to their 2007 album, Underclass Hero.Although the band initially planned to just release a new EP in 2009, frontman Deryck Whibley said that the writing process is going so well that they are now planning a full length release."There was talk about doing an EP and then that turned into other things,: he said in an blog post. "Next thing you know we're sitting here with a whole bunch of songs that we really like.""As to when it will come out," he continued, "I don't know. I would say it's safe to say it will be out this year. Unless for some reason we need to keep going and it pushes it back further. But right now everything is on track and feels good."In related news, the band have also confirmed that they will be releasing a Greatest Hits album, All The Good Shit, worldwide later this year following the popularity of the compilation in Japan.