Beverly Johnson, who rose to fame as a supermodel in the 1970s, wrote in a Vanity Fair essay that Cosby drugged her at his New York City townhouse in the 1980s.
"He was Bill Cosby, he was charming and elegant and kind," Johnson told CBS News correspondent Ben Tracy. "He seemed very concerned and really willing to help me see my goals."
Johnson is probably the most famous of the nearly two dozen women who have accused Cosby. She had conquered the modeling world and was trying out acting when she met the famed comedian.
In the mid-1980s Johnson was auditioning for a role on "The Cosby Show." She said Cosby invited her to his townhouse to rehearse.
"He kept insisting to have this cappuccino, it's the best coffee you'll ever have, and so I relented and I took the coffee. And I took a sip of the coffee and I immediately felt strange and then I took another sip of the cappuccino and that drug was so powerful it just came on like a moving train, and I knew I had been drugged," Johnson said.
"I knew he was trying to take advantage of me, but I knew this goes above and beyond making a pass at a woman," Johnson added. "You don't make a pass at a woman by drugging her."
She does not think Cosby assaulted her, but she said she was nearly unconscious when he dragged her out of his house and put her in a cab. That was after she swore at him several times.
"I just looked him dead in the eye and called him a name," Johnson said.
What did she call him?
"I called him an MF. I said, 'You're an MF, aren't you?'"
She said she used the actual words, and he was a little stunned.
"I wanted him to know that I knew that he drugged me," Johnson said.
She said days after the incident, she called Cosby to confront him, but his wife Camille answered and Johnson never spoke to the comedian again.
She's now coming forward with her story.
"It was the women that have come forward that gave me the courage to come forward... then to hear their stories that were very similar to mine, I knew that I had to say something," Johnson said.
Johnson said women tend not to speak out against powerful men, and she feels that allowed Cosby to continue his alleged behavior.
"Now that I speak to other people in the business in Hollywood, it's one of the best kept secrets in Hollywood," Johnson said. "I most certainly had -- I would not have gone to his home if I had known he had that kind of reputation. Absolutely not."
Cosby's lawyers did not respond to our request for comment on Johnson's claims, but his lawyer has issued blanket denials of "baseless decades-old accusations."