Isaiah Washington thanked his GREY'S ANATOMY castmate Katherine Heigl for speaking out against his homophobic slur towards show actor T.R. KNIGHT. Washington and co-star Patrick Dempsey were involved in an on-set fight last October (06), when the actor reportedly referred to Knight as a "f**got" - a remark he repeated at this year's Golden Globe awards in January (07). But Heigl insists Washington has seen the error of his ways - and was thankful she spoke out against him. She says, "Isaiah thanked me, which I didn't understand. He was almost grateful. I don't know Isaiah well, but he takes his work seriously and he loves his character. "He made a big mistake, and it was thoughtless and boneheaded, and I think he's very sorry and embarrassed. This is something that will have changed the scope of his life."