Louis C.K. has doubled down on his distaste for Donald Trump.

The comedian called the president “a gross, crook, dirty, rotten, lying sack of s—” during an appearance Tuesday night on “The Late Show With Stephen Colbert.”

C.K. emailed a letter to fans last year slamming then-candidate Trump as “an insane bigot” and comparing him to Hitler.

“Please stop it with voting for Trump,” C.K. wrote. “It was funny for a little while. But the guy is Hitler. And by that I mean that we are being Germany in the ’30s. Do you think they saw the s— coming? Hitler was just some hilarious and refreshing dude with a weird comb over who would say anything at all.”

Although he now regrets sending the scathing letter, the comic says he doesn’t take back what he said (“I regret saying it — it doesn’t mean it’s not true”).

The letter made more than headlines — it landed him on the cover of the New York Daily News alongside Trump.

“I guess he’s not as profound as I thought he was,” the comedian said before the audience erupted into applause. “I thought he was some new kind of evil, but he’s just a lying sack of s—.”

He then described Trump as the type of liar who “likes” to lie.

“Someones people lie — ‘That guy lied, they found out he lied.’ Then there’s somebody who lies once in a while and can’t quite stay inside the boundaries of truth. Somebody who lies sometimes,” he began. “Then you have a liar — almost like a problem; they can’t help it, they lie a lot.”

“Then you have just a lying sack of s—,” he added. “They like it — he likes it. He goes, ‘Heh heh, it wasn’t even true. Wasn’t even true. Then I said, ‘They were liars.'”

“It’s just an insane. It’s just gross. He’s just a gross, crook, dirty, rotten, lying sack of s—,” the comedian said.

Louis C.K’s new stand-up special premiered Tuesday on Netflix.