Bill Cosby has admitted to apologising to his accuser's mother over an alleged sexual assault, a Pennsylvania courtroom has heard.

Mr Cosby – the legendary comedian and television star - is on trial this week for allegedly sexually assaulting Andrea Constand, a former employee of his alma mater. Mr Cosby maintains their encounter was consensual, and has pleaded not guilty to aggravated indecent assault.

Ms Constand’s mother testified previously that she had called Mr Cosby to confront him about the incident after her daughter disclosed what had happened.

“I keep harping at him, we kept talking about what had happened,” Gianna Constand recalled of the conversation. “I said the only thing I’d like … from you is an apology.”

According to the elder Ms Constand, she got it. She says Mr Cosby told her, “I apologise to Andrea ... and I apologise to you, mom.”

The jury on Friday heard the comedian’s version of the call, in which he admitted to apologising to Ms Constand’s mother – but only for fear of coming off as a “a dirty old man”.

“I apologised to this woman,” Mr Cosby said, in a deposition read aloud by a detective. “But my apology was, ‘My God, I’m in trouble with these people because this is an old man and their young daughter.”

Bill Cosby: Career in pictures Show all 20 1 /20 Bill Cosby: Career in pictures Bill Cosby: Career in pictures Bill Cosby Winner of his first Emmy for 'I Spy' is Bill Cosby being congratulated by his wife Camille held at Americana Hotel, 1966 Bill Cosby: Career in pictures Bill Cosby Bill Cosby in 'I Spy', 1960s Bill Cosby: Career in pictures Bill Cosby Bill Cosby in July 1973 in Perth Bill Cosby: Career in pictures Bill Cosby Bill Cosby and Richard Pryor in 'California Suite', 1978 Bill Cosby: Career in pictures Bill Cosby Bill Cosby and Elmo in Sesame Street, 1989 Bill Cosby: Career in pictures Bill Cosby Bill Cosby poses for a picture with Florence Griffith-Joyner in June 1989 Bill Cosby: Career in pictures Bill Cosby Comedian Bill Cosby back in 1992 Rex Features Bill Cosby: Career in pictures Bill Cosby A scene from a 1992 episode of 'The Cosby Show' AP Bill Cosby: Career in pictures Bill Cosby US Monica Seles breaks into laughter as she jokes with comedian Bill Cosby during a celebrity match in the stadium at the US Open for the Arthur Ashe AIDS Challenge on 27 August 1995 Bill Cosby: Career in pictures Bill Cosby Bill Cosby meets Toronto Blue Jays' All-Star Joe Carter after the Stars played the Stripes in the Celebrity All-Star game which preceded workouts for the 67th All-Star Game at Veterans Stadium on 8 July 1996 in Philadephia Bill Cosby: Career in pictures Bill Cosby Co-hosts Oprah Winfrey and Bill Cosby joke with each other during the opening of the 2000 Essence Awards 14 April 2000 at Radio City Music Hall in New York City Bill Cosby: Career in pictures Bill Cosby Bill Cosby jokes with baseball great Hank Aaron after they both received the Presidential Medal of Freedom Award from U.S. President George W. Bush during a ceremony on 9 July 2002 at the White House in Washington Bill Cosby: Career in pictures Bill Cosby Bill Cosby poses backstage after winning the 'Bob Hope Humanitarian Award' during the 55th Annual Primetime Emmy Awards at the Shrine Auditorium on 21 September 2003 in Los Angeles Bill Cosby: Career in pictures Bill Cosby 'Tonight Show' host Jay Leno and comedian Bill Cosby laugh during a surprise visit by Cosby to sign a Harley-Davidson motorcycle that Leno is using to raise money for the victims of Hurricane Katrina at NBC studios on 9 September 2005 in Burbank, California Bill Cosby: Career in pictures Bill Cosby Bill Cosby speaks during a taping of 'Meet the Press' at the NBC studios on 14 October 2007 in Washington Bill Cosby: Career in pictures Bill Cosby Bill Cosby at the 12th annual Mark Twain Prize for American Humor at the John F. Kennedy Center on 26 October 2009 in Washington Bill Cosby: Career in pictures Bill Cosby Bill Cosby speaks at the National Action Network's 20th annual Keepers of the Dream Awards gala in New York on 6 April 2011 Reuters Bill Cosby: Career in pictures Bill Cosby Bill Cosby during the 100th anniversary celebration of the Beverly Hills Hotel & Bungalows supporting the Motion Picture & Television Fund and the American Comedy Fund, 2012 Getty Images Bill Cosby: Career in pictures Bill Cosby Bill Cosby speaks onstage at the Thurgood Marshall College Fund 25th Awards Gala on 11 November 2013 in Washington Bill Cosby: Career in pictures Bill Cosby Bill Cosby performs at the Treasure Island Hotel & Casino on 26 September 2014 in Las Vegas

The deposition in question stems from a 2005 lawsuit that Ms Constand filed after detectives unexpectedly closed her sexual assault case. The deposition was unsealed in 2015, just seven months before detectives reopened the case against Mr Cosby.

Mr Cosby is not expected to testify at the trial, so the deposition is one of the only opportunities the jury will have to hear about the incident in his voice.

Jurors on Thursday heard excerpts from the deposition of in which Mr Cosby recounted his previous encounters with Ms Constand.

Mr Cosby described one instance, in which he admits to sexually touching the plaintiff, as such: “I don’t hear her say anything. And I don’t feel her say anything. And so I continue to go into the area that is somewhere between permission and rejection.”

Asked if he ever request Ms Constand’s permission, Mr Cosby said, “She did not stop me. And I wanted to go.”

The jury also heard from sections of the deposition in which Mr Cosby confessed to giving Ms Constand pills, which he called “friends”. Mr Cosby maintains the pills were Benadryl; the defence has suggested they may have been something stronger.

Mr Cosby said in a previous police interview that he used Benadryl as a sleep aid, and that he becomes drowsy and falls asleep shortly after taking them.

Ms Constand has described herself as “frozen” and seeing double after taking the pills Mr Cosby provided her.