Green Day is a music group that has sold millions of records.
Green Day is an American punk rock band formed in 1986 by lead vocalist and guitarist Billie Joe Armstrong and bassist Mike Dirnt . The band 's rock opera , American Idiot ( 2004 ) , reignited the band 's popularity with a younger generation , selling six million copies in the U.S. . Green Day has sold more than 85 million records worldwide .