Former Coronation Street star Ken, who was thrown out of CBB on Monday night, apparently got too close for comfort as he recorded the Safestyle double glazing commercial with Sarah Whitefoot.
Recalling her day on set with Ken in 2002, Sarah told The Sun that she believes he deliberately fluffed his lines so he could spend more time with her.
Sarah, now 35, said: "The filming took place years ago but it was such a disgusting experience I can remember it like it was yesterday."
She added: "Within minutes of meeting he was putting his arm around me and slapping my bum. He couldn't take his eyes off my cleavage.
"I felt so uncomfortable I remember my instant reaction was to pull my prop card, which had the slogan 'BOGOF', over me."
Reveal has contacted Ken's rep for a comment.
On Monday, Ken was removed from the Celebrity Big Brother house following warnings about his behaviour and choice of language.
In scenes aired on Channel 5 that evening, Ken was shown discussing the female housesmates' "a*ses", insulting Patsy Kensit's heritage and using the word "negro" when talking about boxer Frank Bruno.
Following his removal from the house, Ken appeared on Loose Women yesterday and denied being a racist.
He said: "I apologise unreservedly to everybody who watched that programme. I apologise if I disappointed you by saying what I said. It was banter in a odd situation.
"I understand entirely that I've upset a lot of people from everywhere in the world, not just this country, from Africa, from the Caribbean.
"I apologise unreservedly to you now for upsetting you and I hope you accept that apology. I am not a racist, never have been. I taught black children in London and everywhere."
Ken is the second housemate to be removed from this year's CBB following the show's launch a week ago. On the weekend, Baywatch star Jeremy Jackson was ejected from the show after exposing Chloe Goodman's naked breast.
US actor Jeremy has since received a police caution for common assault and appeared on This Morning, to explain his side of the story.