Rolf Harris and his daughter Bindi have both been accused of lying to the jury in the entertainer's child sex abuse trial which has taken a dramatic turn with new evidence coming to light.

Video has emerged of the star at a charity sporting event in Cambridge in 1978 less than a week after Harris insisted he'd never been to the city until three or four years ago.

The 84-year-old is charged with groping a teenage girl in Cambridge in the mid-1970s.

The jury on Monday was shown footage of the Australian participating in Star Games at Jesus Green in Cambridge in 1978.

Harris was captain of the "Theatre" team, participated in a swimming race and painted a mural on a wall, Southwark Crown Court heard.

Prosecutor Sasha Wass QC said the video proved Harris was lying when he said he hadn't been to Cambridge until recently.

"That was a deliberate lie, wasn't it?" Ms Wass asked the artist and singer.

Harris replied: "No ... a lapse of memory."

He said he had no idea he was in Cambridge until he was shown the Star Games footage.

Ms Wass appeared incredulous, asking: "You didn't know where you were?"

"I don't think any of us (in the show) did," Harris replied.

"We all went on a bus to get there. We were deposited on the green.

"I was in Cambridge but I didn't know it was Cambridge."

The alleged victim initially said she'd been groped by Harris at what she thought was a celebrity version of It's a Knockout in around 1975 when she was 13 or 14. She turned 16 in early 1978.

Following her father into the witness box Bindi Nicholls cried when speaking about her former best friend - another complainant in the case - who alleges Harris abused her from the age of 13.

Ms Nicholls backed her dad's claim that the pair actually had a consensual "affair" which started after the family friend turned 18.

Ms Wass grilled Harris's daughter about when in 1980 the family moved from south London to Bray, west of the capital.

The date is important as the alleged victim claims she was assaulted in Harris's new home before she turned 16 in April 1981.

"I'm suggesting you and your father have colluded to give the same evidence," Ms Wass said to Ms Nicholls on Monday.

But the entertainer's daughter insisted: "No we hardly talk my dad and I. It's not really something we sit down and talk about."

Ms Nicholls said it was "ridiculous" and "laughable" for her childhood friend to claim Harris performed oral sex on her when she was 15 while Bindi slept in the next bed.

Four weeks ago the court was told the alleged victim had revealed to doctors and counsellors, from the mid-1990s on, that she'd been abused by Harris.

Ms Wass on Monday wanted to know why Ms Nicholls had refused to release her counsellor's notes that the prosecutor argued could be crucial.

They might show, the barrister said, whether Ms Nicholls had told her therapist if her friend had been abused by Harris or had an affair with him.

The entertainer's daughter said the notes were "private".

Ms Wass suggested Ms Nicholls was financially dependent on Harris who provides her a monthly income.

She read out a mid-2012 email from Ms Nicholls to her father in which she asked if she was the sole inheritor of his STG11 million ($A20 million) estate.

In the email she writes: "It's like being told that you will be winning the lottery at some point so you get excited and dream about the things that you could do."

Harris is charged with indecently assaulting four girls in the UK between 1968 and 1986. He denies all 12 counts.