Pearl Jam is an American rock band formed in Seattle, Washington, in 1990. One of the key bands in the grunge movement of the early 1990s, Pearl Jam has outsold and outlasted many of its contemporaries from the early 1990s, and is considered one of the most influential bands from that decade, dubbed "the most popular American rock and roll band of the '90s". Since 1998, the band's lineup has comprised bassist Jeff Ament, guitarists Stone Gossard and Mike McCready, vocalist/guitarist Eddie Vedder and drummer Matt Cameron; keyboardist Boom Gaspar has also been a session and touring member with the band since 2002. Drummers Dave Krusen, Matt Chamberlain, Dave Abbruzzese and Jack Irons are former members of the band.