It's been five years since their last album, and Green Day's finally back with a new album, 21st Century Breakdown, out today!

The band -- Billie Joe Armstrong, Mike Dirnt, and Tre Cool -- will have a string of appearances including Saturday Night Live tomorrow and the Good Morning America Concert Series next Friday, May 22.

The first single, "Know Your Enemy," is already a huge hit... check it out at greenday.com.

What do you think of Green Day?

Photo: Courtesy of Phil Mucci/Warner Music