Adam Keefe Horovitz (born October 31, 1966), better known as Ad-Rock or King Ad-Rock, is an American musician, guitarist, rapper, producer, and actor. He is best known as a member of the pioneering hip hop group, Beastie Boys.
Horovitz was born in South Orange, New Jersey, the son of Doris Keefe and playwright Israel Horovitz. He is Jewish and began his musical career with a stint in the punk rock band, The Young and the Useless, who would often perform with Beastie Boys. When Beastie Boys guitarist John Berry quit, Horovitz was an obvious choice to replace him . He also played with Los Angeles based hardcore legends, D.F.L (Dead Fucking Last). He played bass and produced their first album 'My Crazy Life'. Tom Davis, brother-in-law to fellow Beastie Boy Member Mike D, sang vocals. Adrock, with Mike D and MCA, would endure as the classic Beastie Boys line-up.
In addition to his work with Beastie Boys, Horovitz has released music with a side-project called BS 2000 and has produced albums for Teriyaki Boyz and Northern State. For a time, he also pursued an acting career, with appearances in films such as Lost Angels, Roadside Prophets, and A Kiss Before Dying.