Rolf Harris has admitted in a London court that he may have sexually admired his daughter's 13-year-old friend when she joined his family on an overseas holiday in the late 1970s.
Harris was grilled by prosecutor Sasha Wass QC about his "ridiculous" claim he'd had a 10-year consensual affair with Bindi's friend which began when she was 18.
The main complainant in the case alleges Harris first indecently assaulted her on the 1978 trip to Canada, Hawaii and Australia, and then over the subsequent decade.
"This was child abuse, grooming, you effectively psychologically dominated this girl into womanhood," Ms Wass said.
The prosecutor suggested that when Harris said Bindi's friend looked great in a bikini on the holiday he was actually saying she had a great body because the bathing suit was just a few pieces of small fabric.
"I suppose so," Harris replied in a soft voice.
Asked whether that meant, in hindsight, he admired his daughter's friend sexually at the age of 13, the entertainer said: "It's possible, yes."
Ms Wass argued that admission suggested everything the alleged victim had said was therefore "realistic".
"No," Harris replied. "Because it didn't happen."
Ms Wass claimed the 84-year-old had tailored his entire case around a letter he wrote to the alleged victim's father in 1997 apologising for his behaviour.
"You've given away rather too much in this letter," the prosecutor said, adding it didn't make sense if the pair had had a consensual relationship.
In the letter, previously read out in court, Harris said he'd asked the alleged victim: "Why did you never just say no?"
Ms Wass said that was an odd thing to say "if she was the person throwing herself at you".
Why hadn't the TV presenter stated in the letter that the complainant instigated the sexual encounters, she demanded to know.
The barrister also made much of Harris's admission in the letter that: "When I see the misery I have caused (the alleged victim) I am sickened by myself."
"What had you done to make her miserable?" Ms Wass asked repeatedly.
Eventually Harris said the alleged victim may have been depressed because the affair had ended and "I took it all on board as I tend to do".
The prosecutor then asked why Harris had written that he'd "begged her for forgiveness".
"It makes no sense," Ms Wass said of Harris's account. "It doesn't have the ring of truth about it."
Harris admitted the pair "hardly ever spoke", even when they went on a walk near his home and, according to the entertainer, she performed oral sex on him in public.
"Did you treat her as a human being at all?" the prosecutor asked.
"There wasn't a friendship at all," she continued.
"She was just there for sex (even) on your account."
To that Harris admitted: "It would seem so."
At one point during the gruelling cross-examination the artist and singer asked if he could proffer additional information.
He then stated it would have been "physically impossible" to perform oral sex on the complainant while looking over at his daughter asleep in a nearby bed, as the alleged victim has claimed.
The entertainer said the sexual encounters - about eight in total over 10 years - were "isolated occasions".
But he insisted they "stemmed from a feeling of love and friendship" and there was "warmth and affection".
Harris yesterday admitted having an affair with his daughter's childhood friend but said it was "ludicrous" to suggest he'd had sex with her when she was underage.
He also admitted to a second affair with a female lodger in the mid-1990s.
Ms Wass today said there was no disputing the Australian was a "brilliant and polished performer" but she told Harris: "This case, as you know, is not a talent show."
She said it was about whether he had a "darker side" beneath his friendly and loveable exterior.
Ms Wass said the fact he'd concealed two affairs from his family and friends meant he was good at disguising a dark side. "Yes," Harris admitted.
The 84-year-old is charged with indecently assaulting four girls in Britain between 1968 and 1986. He denies all 12 counts.