SANTA MONICA, CALIFORNIA (REUTERS) - A woman who accused Bill Cosby of sexually assaulting her in the mid-1970s began her court testimony on Monday (June 6), describing how she and a friend met the comedian as teenagers and accompanied him to the famed Playboy Mansion.

Ms Judy Huth, who has filed a civil lawsuit against Cosby, 84, for unspecified damages, told jurors she was playing frisbee at a public park on a weekday when she noticed a movie filming nearby.

She and a friend, Ms Donna Samuelson, walked closer and recognised Cosby, Sidney Poitier and other actors.

Cosby approached the girls and they "bantered", she said, before he invited them to meet him the following Saturday at a tennis club. She and Ms Samuelson were "excited", she said.

"We were kids. It was a celebrity. It was out of the norm, that's for sure," Ms Huth said.

She said she and Ms Samuelson met Cosby at the tennis club, then followed him by car to his home, played a few games of pool and followed him to another location.

Ms Huth realised it was the Playboy Mansion when Cosby pointed out a picture of Playboy founder Hugh Hefner on the wall.

Ms Huth, 64, is set to continue her testimony on Tuesday.

In her lawsuit, Ms Huth said Cosby forced her to perform a sex act while she was at the mansion.

She previously said the incident occurred in 1974, when she was 15, but recently said she now believes it was 1975.

The civil trial in California, one of the last legal cases against Cosby, is taking place 11 months after Cosby was freed from prison when Pennsylvania's highest court threw out his sexual assault conviction in a different case.

Cosby's lawyer Jennifer Bonjean said in opening statements that the alleged assault of Ms Huth was a "fabrication", though Cosby did not dispute that he invited Ms Huth and her friend to the mansion.

"The evidence is going to show that Ms Huth is not telling the truth," Ms Bonjean said.

Ms Huth's friend, Ms Samuelson, recounted her recollection of events earlier on Monday.

Ms Bonjean challenged her account of the mansion visit, noting that Ms Samuelson had recalled playing a Donkey Kong arcade game, which was not introduced until 1981.

Cosby is not expected to attend the trial.

The comedian and actor is best known for his role as the lovable husband and father in the television comedy series The Cosby Show (1984 to 1992), earning him the nickname "America's Dad".

But his family-friendly reputation was shattered after more than 50 women accused him of sexual assaults over nearly five decades.

In 2018, Cosby was found guilty of drugging and molesting Ms Andrea Constand, an employee at Temple University in Philadelphia, in his home in 2004.

Pennsylvania's Supreme Court overturned Cosby's conviction in June 2021, after Cosby had served more than two years of a three- to 10-year sentence.

The court said Cosby should not have faced the charges because a previous district attorney had publicly promised in 2005 not to prosecute him.

In March, the United States Supreme Court declined to review that decision.