Another woman has come forward claiming that superstar comedian Bill Cosby (search) slipped her a knockout pill and sexually assaulted her, months after she ended a consensual affair with him.

Beth Ferrier (search), who now lives in Denver, told the Philadelphia Daily News that, 21 years ago, she was an aspiring model who met the comic in New York and started a brief fling.

Months later, after the affair had ended, Cosby passed through Denver and met his old flame backstage before a performance at a now-defunct club.

"He said, 'Here's your favorite coffee, something I made, to relax you,' " Ferrier, now 46, told the newspaper.

Ferrier said she drank the coffee and passed out.

"I woke up and I was in the back of my car all alone," she said. "My clothes were a mess. My bra was undone. My top was untucked. And I'm sitting there going, 'Oh my God. Where am I?' What's going on? I was so out of it. It was just awful."

She said Cosby sent over a security guard to help her get home. Later, she decided to confront the comic at his hotel, but he blew her off, claiming, "You just had too much to drink," she said.

The newspaper said Ferrier has passed a polygraph test about her claims.

Cosby's lawyer, Andrew Schau, told The Post, "We will not be commenting on any of these stories."

Ferrier is Jane Doe No. 5 in Andrea Constand's civil lawsuit against Cosby, filed in March.

Constand, the former director of operations for the women's basketball program at Temple University in Philadelphia, Cosby's alma mater, has also accused Cosby of drugging and groping her in January 2004.

There are 11 other anonymous witnesses in addition to Ferrier. A 13th woman, California attorney Tamara Green (search), has allowed Constand to use her name in the lawsuit.

Cosby has said he gave Constand some over-the-counter Benadryl because she complained of tension and sleeplessness.

He has denied sexually molesting her. She sued after a criminal investigation resulted in no charges against the "Cosby Show" star.

Hearing about Constand's case led Ferrier to come forward.

"I was like, 'Oh, my gosh!' It's just like what happened to me," Ferrier, who has three children and is going through her second divorce, told the Philly Daily News. "That explains it. I've not, all these years, had an explanation.

"The impact on my life has been monumental," Ferrier added. "You can't keep secrets if you're being hurt, if you're being victimized. He made me feel like I'd done something wrong."