CNN anchor Anderson Cooper on Friday told prominent Trump supporter Jeffrey Lord that he would defend the president even if he "took a dump on his desk."

"If he took a dump on his desk, you would defend it," Cooper said.

Lord appeared momentarily stunned before he and other guests started to laugh.

"I mean, I don't know what he would do that you would not defend," Cooper said. "I mean, you're a loyal guy, I think that speaks well of you."

Cooper had been asking Lord about President Trump calling former FBI Director James Comey "a nut job" in his meeting with Russian officials one day after firing him.

Cooper apologized to Lord a short time later for being "a little crude."

"I like having your voice on here and I think you're an important voice to have, so I'm sorry I was a little crude. And you defend the president very well, and that's your job," he said.

Cooper later repeated his apology on Twitter and said he'd been "unprofessional."

"I regret the crude sentence i spoke earlier tonight and followed it up by apologizing on air. It was unprofessional. I am genuinely sorry," Cooper tweeted.