LOS ANGELES (AFP) - A vandal scrawled the word "rapist" on Bill Cosby's Hollywood Walk of Fame star, as a new accuser emerged Friday claiming the veteran comic raped her and 12 other former Playboy bunnies.

The word was written three times on the star on the storied Walk of Fame, the stretch of celebrity themed sidewalk visited by millions of tourists every year.

The Hollywood Chamber of Commerce, which looks after the stars and organises ceremonies for new inductees, acted quickly to have the graffiti removed.

"The Hollywood Walk of Fame is an institution celebrating the positive contributions of the inductees," it said in a statement.

"When people are unhappy with one of our honorees, we would hope that they would project their anger in more positive ways than to vandalise a California State landmark.

"The star is being cleaned up at this time," it added - but not before pictures of the defaced star appeared on social media.

AFP and other cameramen arrived in time to see the star being cleaned.

Around 20 women have now accused the 77-year-old Emmy and Golden Globe winner of sexual assault and even rape in alleged incidents dating mostly from decades ago.

So far only one has taken legal action: former Playboy hostess Judy Huth, who filed a lawsuit in Los Angeles on Tuesday claiming Cosby assaulted her at Hugh Hefner's Playboy mansion in 1974.

NEW ACCUSER

On Friday, a new accuser came forward, another former Playboy "bunny" who claimed that she and at least 12 other fellow employees were raped by Cosby.

P.J. Masten, who began working as a Playboy waitress in 1972, claimed that Cosby drugged and raped her after inviting her to his hotel room in Chicago, and offering her a glass of what he said was Grand Marnier.

"The next thing I knew, it was 4 o'clock in the morning," she told CNN. "I woke up in a bed naked, bruised. He was laying next to me, and I slithered out of the bed... I got myself together, I went downstairs, I got in a cab, and I went home," she said.

But she was certain that he had raped her while she was unconscious.

"This man has to be held accountable. He's a serial rapist. He's been that way since the 1960s," she told the broadcaster.

She was not the only former "bunny" to be raped by the entertainer, she claimed.

There were "12 former bunnies that I know of that are ashamed to come forward, frightened to come forward, married with families (and) don't want to come forward," Masten said.

"But they were also drugged and raped by Bill Cosby."

On Thursday, Cosby's lawyer, Marty Singer, counter-sued Huth in the LA Superior Court, accusing her of trying to extort up to US$250,000 from him in return for her silence.

The attorney also sought to undermine a key part of Huth's legal claim: under California law she had to prove that she had only become consciously aware of the alleged sex abuse within the last three years.

"The only way that an alleged victim of childhood sexual abuse would be able to assert an otherwise time-barred claim is to allege that the psychological injury... had been repressed and was only discovered within the last three years," he wrote.

But he said Huth had "unsuccessfully tried to sell her story to the tabloids nearly a decade ago. This fact belies the allegation... that (the) plaintiff only just discovered the basis for her claims within the past three years."

Cosby is famous for his role in The Cosby Show that aired in the 1980s and 1990s.