Keith Diamond (born Vincent Ford, Jr. on March 26, 1962 in Jamaica, New York) is an African American actor and voice actor. He is especially known for his roles as Agent J on Men In Black: The Series and as recurring character Greg Clemens on The Drew Carey Show. Over his career, Diamond has appeared in guest spots on numerous television series, including Charmed, Martin, ER, and LAX. He also guest-starred in Criminal Minds in the episode, "Plain Sight" as Detective Cornelius Martin who aids the BAU in capturing a serial rapist/murderer named the '"Tommy Killer".