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 the Beastie Boys. Horovitz was born to Doris Horovitz (née Keefe) and playwright Israel Horovitz and raised in Manhattan, New York. He was reportedly born in South Orange, New Jersey, but he has denied this in interviews and on stage. His sister is producer Rachael Horovitz.