In arguably his most striking gaffe in Saturday’s bizarre BBC interview, Prince Andrew claimed that his onetime pal, pedophile Jeffrey Epstein, “quite obviously conducted himself in a manner unbecoming.”

The word choice prompted his interviewer to snap back, “Unbecoming? He was a sex offender!”

The foot-in-royal-mouth moment came toward the end of his hour-long sitdown with BBC journalist Emily Maitlis.

She was asking Andrew whether he had any regrets over his friendship with Epstein.

One of Epstein’s young “sex slaves,” Virginia Giuffre, has accused Epstein of three times trafficking her to the royal when she was just 17 and 18 years old; a photo of Andrew with his arm around the teen has also dunned him in recent years.

“Do I regret the fact that he has quite obviously conducted himself in a manner unbecoming — yes,” Andrew answered Maitlis.

The reporter looked almost aghast as protested “He was a sex offender!”

Andrew struggled to recover, stammering, “Yeah, I’m sorry.”

He quickly added, “I’m being polite, in the sense that he was a sex offender.”

Twitter quickly hated on the gaffe, with critics weighing in on #unbecoming.

“#unbecoming has to be the new # for absolutely horrific behaviour. I punched a kitten #unbecoming of #PrinceAndrew,” tweeted “L copeland.”

The hashtag #NoSweat, also circulated — a reference to Andrew’s claim earlier in the BBC interview that Giuffre couldn’t possibly have complained that he was a “sweaty” dancer back in 2001.

“Because I have a peculiar medical condition,” Andrew “explained.”

“Which is that I don’t sweat, or I didn’t sweat at the time . . . because I had suffered what I would describe as an overdose of adrenaline in the Falklands War when I was shot at. And I simply — it was, it was almost impossible for me to sweat.”

Other mocking hashtags were #ForAMan and #pizzaexpress.

In another weird denial of ever having even met Giuffre, Andrew had claimed that he would have remembered having sex with her because he’s male.

“Without putting too fine a point on it,” he argued, “If you’re a man, it is a positive act to have sex with somebody. “You have to take some sort of positive action and so therefore if you forget it’s very difficult to try and forget a positive action and I do not remember anything.”

The #pizzaexpress hashtag came in response to his claim that on the first night Giuffre claims she was trafficked to him, in 2001, he was actually at home with the kids — a night he remembers because he took Princess Beatrice to “the Pizza Express in Woking.”

“I remember it weirdly, distinctly,” he insisted.