Laura Goldman, who spoke to Maxwell at her home as recently as three weeks ago, described the Prince and Ghislaine Maxwell's relationship as "very, very, very close."
Ms Goldman told ITV News: "I wonder if [Ghislaine's] father hadn't died whether she might have been the Duchess of York."
Ms Maxwell father, Robert Maxwell, was the British media mogul who died at sea in 1991 after going missing on his yacht.
When asked if their relationship was so close it could be described as "personal," Ms Goldman said: "Yes, yes I think so."
The Prince would, she said "do almost anything for her [...] he would have walked across coals for Ghislaine."
Ms Goldman described how she spoke to Ghislaine Maxwell just week before her arrest and described her as "nervous".
"She knew she was in trouble," she said of her friend.
Ms Goldman also recalled meeting Prince Andrew in New York 2010 - on the trip the royal made to end his friendship with Jeffrey Epstein - following his conviction for sex offences.
"First of all, he does sweat," she said recalling the moment she shook his hand at Ghislaine Maxwell's New York home.
The Duke of York and Maxwell were on their way to a party, she said, saying the Prince was, in her opinion, "nice but dull".
She added: "He is stupid. He is spoiled. He is entitled. He thought they were rolling out the red carpet for him.
"They really liked each other, they really trusted each other," Ms Goldman said of the close relationship between the Prince and Maxwell.
And it is why she believes that Maxwell will not "implicate" the Queen's son, when she is questioned by the FBI.
Ms Goldman said: "Will she implicate Prince Andrew?
"I would say hell would have to freeze over. But she is facing 35 years in jail so maybe hell has frozen over?"
She estimated there would be just a "two per cent" chance of Maxwell turning against her old friend.
It was Ghislaine Maxwell who first introduced Prince Andrew to Jeffrey Epstein and the Prince admits he met up with Maxwell as recently as last year.
As for the Prince's claim that he never saw anything in any of Epstein's properties which led him to suspect any wrongdoing, Ms Goldman told ITV News:
"I really think you're giving Prince Andrew too much credit for not being a narcissist and thinking about anyone other than himself [...] I don't think he looks at his surroundings."
She added: "I don't think that he is that smart to even question.
"And you are misunderstanding how tight he was with Ghislaine and he would trust her with his life.
"So he didn't have any reason to look around."