The 44-year-old actor, musician and activist invited Dr Bharat Pankhania, an expert in infectious disease management from University of Exeter Medical School, onto his GB News show to discuss a new report on the vaccination roll out.
Asked to give his opinion Pankhania said: "I sometimes wonder why you exist, to be honest with you.
After the good doctor started to sermonise about Brexit in relation to vaccine harms, the remainder of the interview was me trying not to giggle. https://t.co/UwixTT15F7
— Laurence Fox (@LozzaFox) April 27, 2023
"A lot of these things that you spew out, just send things that are worrisome to people, are not verified, not factual.
"You just have your own agenda, that's what I think. You are just spewing out your biased views. That's how I feel about you."
Fox appeared to be briefly lost for words, before finally replying: "I wasn't asking you what you felt about me, I was asking you what you felt about the discussion."
The doctor went on to claim his appearance on the show was an "ambush" as he had been invited to a one-on-one interview with Fox, only to find himself in a panel discussion about a critical report of the Medicines and Healthcare products Regulatory Agency's (MHRA) roll out of the vaccines.
Pankhania said of the coronavirus vaccination programme: "All in all on the balance of good versus harm - the good outweighs the harm by a large, large margin."
Fox later tweeted: "After the good doctor started to sermonise about Brexit in relation to vaccine harms, the remainder of the interview was me trying not to giggle."
The actor is best known for playing detective James Hathaway in long-running ITV drama Lewis.
He become the centre of a media storm after voicing controversial opinions on political debate show Question Time in January 2020.
During the coronavirus pandemic he has been outspoken against lockdown restrictions and in May 2021 he stood for London Mayor, only to lose his £10k after getting just 1.8 per cent of votes.
He was invited to join GB News presenter in October 2022.
A member of the Fox acting dynasty – his father is James Fox, his uncle is Edward Fox and his cousins are Freddie and Emilia Fox.
He was married to actor and pop singer Billie Piper from 2007 to 2016 and they share two sons Winston, 14, and Eugene, 10.
Watch: Laurence Fox campaigning to be London Mayor in 2021