Sources close to Defence Secretary Sir Michael Fallon have confirmed he was once rebuked by a journalist for putting his hand on her knee during dinner.
Radio presenter Julia Hartley-Brewer had recounted the “mildly amusing” incident without naming Sir Michael.
After his identity was revealed in The Sun, she tweeted saying she had not been “remotely upset or distressed”.
A spokesman for Sir Michael said he had apologised when it happened in 2002.
Ms Hartley-Brewer, a former political editor of the Sunday Express and regular political commentator, has criticised “wild rumours and claims” circulating at Westminster.
She said she did not consider herself a victim after the incident which happened over dinner at the Conservative Party conference.
After the minister kept putting his hand on her knee, she said: “I calmly and politely explained to him that, if he did it again, I would ‘punch him in the face’.
“He withdrew his hand and that was the end of the matter.”
A spokesman for Sir Michael said: “He had apologised when the incident happened 15 years ago and both Julia and he now considered the matter closed.”
It comes amid allegations about sexual harassment at Westminster.