Television presenter Justin Lee Collins's relationship with an ex-girlfriend accusing him of harassment brought out "the demon" in him, a court heard.
Collins, 38, had a seven-month relationship with video games public relations worker Anna Larke last year.
A jury at St Albans Crown Court, in Hertfordshire, has heard a secret recording Ms Larke, 38, made of the entertainer verbally abusing her during a row last July.
On the recording, the entertainer says to her "You bring the f****** demon out in me" as he insults her with a tirade of grossly offensive terms.
The "demon" comment was previously inaudible to the court but a transcript of it was used by prosecuting barrister Peter Shaw during Collins's cross-examination. Collins, who came to fame with Channel 4's The Friday Night Project, said the "rant" was completely out of character and it sounded "like someone else".
Mr Shaw said: "You are telling her there is something about this relationship, something about her, that brings the demon out in you." The father-of-two said: "That's not true."
Collins was in "meltdown", he told the jury of nine women and three men after his relationship with the recovering alcoholic hit rock bottom.
Collins met Ms Larke in 2006 at the Golden Joysticks Awards which he hosted in London. The following year they embarked on an affair behind his wife Karen's back, which lasted until 2008. The pair split up but resumed their relationship after the star's marriage broke down in late 2010. Ms Larke moved in with Collins in January last year after he left the marital home in Bristol, but problems quickly developed.
Collins, of Kew, south west London, denies harassment.
The trial was adjourned until Friday when counsel will make closing speeches and Judge John Plumstead will sum up.