US comic Bill Cosby served actress Heidi Thomas spiked wine that made her drowsy for four days in 1984, she has told his trial.
Ms Thomas testified that she woke up to the sight of a naked Mr Cosby attempting to force himself on her.
She is one of 50 women who have accused him of sexual molestation.
Mr Cosby, who is being retried on charges of sexually assaulting ex-basketball player Andrea Constand in 2004, denies the charges against him.
Ms Thomas, an aspiring actress at the time of the alleged assault on her in 1984, said that she met Mr Cosby for career coaching.
She told the court that Mr Cosby asked her to read a monologue of a character who was drunk, persuading her to drink white wine.
She said she recalled "only snapshots" of the next four days.
"The next thing, I remember waking up on a bed. I have clothes on, he did not. I was lying down. He was forcing himself in my mouth," Ms Thomas said.
Mr Cosby has been charged with aggravated indecent assault of Ms Constand, which could carry a prison sentence of up to 10 years.
He says that any contact between himself and his accusers was consensual.
All but Ms Constand's allegations are too old to be prosecuted.
Mr Cosby's lawyer launched a blistering attack on Ms Constand in the defence's opening remarks, describing the Canadian former basketball player as a "con artist".
Thomas Mesereau said that Ms Constand "was madly in love with [Mr Cosby's] fame and money".
"She's now a multimillionaire because she pulled it off," Mr Mesereau told the court
Mr Cosby first went on trial in 2017 for allegedly molesting Ms Constand, however the jury failed to reach a verdict, with the judge declaring a mistrial.
The existence of the civil settlement between Mr Cosby and Ms Constand was known about at the time of the first trial.
However Judge Steven O'Neill ruled that the amount, previously kept confidential, could be revealed to the jury in the course of the new trial.
The retrial takes place in the light of the #MeToo movement.
The campaign has raised awareness of alleged sexual misconduct by a number of powerful media figures.
