LOS ANGELES -- The heated controversy at ABC's top show, "Grey's Anatomy," boiled over Thursday as the network rebuked co-star Isaiah Washington for an anti-gay comment and Washington issued a lengthy apology.

"His actions are unacceptable and are being addressed," the network said in a statement.

During a backstage interview Monday at the Golden Globes, where "Grey's" won as best TV drama, Washington denied involvement in a heated on-set incident, during which an anti-gay remark was uttered. In his apology Thursday, Washington acknowledged "repeating the word Monday night."

Washington said: "I apologize to T.R. [Knight, his "Grey's" co-star], my colleagues, the fans of the show and especially the lesbian and gay community for using a word that is unacceptable in any context or circumstance. I marred what should have been a perfect night for everyone who works on 'Grey's Anatomy.' I can neither defend nor explain my behavior. I can also no longer deny to myself that there are issues I obviously need to examine within my own soul, and I've asked for help."