MSNBC host Thomas Roberts apologized on Wednesday after calling New York City mayoral candidate Anthony Weiner's former sexting partner Sydney Leathers "batsh*t" on air.

During a segment about the latest twists and turns in Weiner's run for mayor, Roberts played a video clip of Leathers speaking with radio host Howard Stern.

"I feel like he lured me into this situation," she explained to Stern. "And then, he didn't want to own up to it. What p*ssed me off was him on the campaign trail saying, 'Oh, I've changed' and trying to act like he has this perfect marriage now and everything peachy."

"I was like, bullsh*t," she added. "I am proof that you have not changed."

"Meanwhile, this chick is so batsh*t," Roberts quipped before catching himself. "I mean, excuse me, bat-you-know-what. Excuse me!"

The MSNBC host pointed out that Leathers was reportedly considering a deal to film a porn parody of her sexting affair with Weiner.

"So, that's why I say that this whole thing is such a big mess," he insisted. "And I do want to apologize that I had the slip of the tongue right there. That was not very professional on my part. I do apologize."

Weiner campaign spokesperson Barbara Morgan also apologized on Tuesday after calling a former campaign intern a “b*tch” and a “sl*tbag” and a "tw*t."

Watch this video from MSNBC, broadcast July 31, 2013.