New Grey's Anatomy Drama Part 1

There's trouble brewing among the cast of Grey's Anatomy. Again.

At the Golden Globes on Monday, Katherine Heigl slammed her costar, Isaiah Washington, for using a slur about fellow cast member T.R. Knight, who confirmed exclusively to PEOPLE in October that he is gay.

At issue was a statement Washington made in the Golden Globes press room when he was asked about an alleged on-set incident between himself and Knight. "No, I did not call T.R. a faggot," he said, according to Access Hollywood. "Never happened, never happened."

Heigl, who is close friends with Knight, criticized Washington's statement. "I'm going to be really honest right now, he needs to just not speak in public. Period. I'm sorry, that did not need to be said, I'm not okay with it."

After the comments in the press room, Washington continued to address questions about the alleged on-set incident, telling Access: "There is no way I could do anything so vile, and so horrible, not only to a castmate, but to a fellow human being."

He also said that he has completely made up with fellow costar Patrick Dempsey after the two had a scuffle in October.

"I kiss Patrick Dempsey," said Washington. "We sing 'Ebony and Ivory' every day since the so-called incident and it hasn't come up."