Being a standup comedian, it's no surprise that Louis C.K. isn't afraid to criticise others - and he is most certainly not drawing a line with Donald Trump.

The comedian appeared on The Late Show with Stephen Colbert to promote his new Netflix stand-up special when the President came up in conversation.

C.K. decided to break down the levels of 'being a liar' to express his views on Trump - on the scale, he believes the US President to be ”...a gross, dirty rotten, lying sack of shit.“

He continued: “I thought he was some new kind of evil but he’s just a lying sack of shit."

After Colbert singled out a Trump supporter in the audience, C.K. merely described him as a victim of his lying.

“He lied to him. He didn’t lie to me. Everybody else was like, ‘Yeah, no, that’s not true.’ But that guy bought it.”

You can watch the full clip below.

C.K.'s latest standup, which is now available to view on Netflix, is a "typically barbarically honest" set - you can read our review here.