Beastie Boys were an American hip hop group from New York City, formed in 1981. For the majority of their career, the group consisted of Michael "Mike D" Diamond (vocals, drums), Adam "MCA" Yauch (vocals, bass) and Adam "Ad-Rock" Horovitz (vocals, guitar).
For the majority of their career the Beastie Boys had 4 members
Incorrect as only had 3 members. Confused the system as it found the list hard to parse.