Fox News host Tucker Carlson responded Wednesday to a now-viral video of an unaired interview in which he swore at a guest, calling him a “moron” and a “tiny brain,” by apologizing for his use of profanity but defending his fiery reaction as “entirely accurate.”

“I did what I try hard never to do on this show, and I was rude,” Carlson said in a video posted to Fox News’s website about his exchange with Dutch historian Rutger Bregman. The host later added, “There is some profanity and I apologize for that. On the other hand, it was genuinely heartfelt. I meant it with total sincerity.”

Last week, Carlson invited Bregman onto his show following the historian’s January appearance at the World Economic Forum in Davos, Switzerland. Bregman made headlines worldwide after he excoriated the Alpine conference’s attendees — a who’s who of global elites — for tax avoidance.

But viewers never saw Carlson’s interview with Bregman, who wrote on Twitter last week that the host called him a “f---ing moron.” In another tweet, Bregman said he had a recording of the entire exchange, prompting many to push for the video to be released.