It took TWO women to wax Robin Williams for 'Greatest Dad' nude scene?

Robin Williams admits to the Dish Rag that it took two women to de-fuzz him for his full-frontal nude scene in Bobcat Goldthwait's brilliant dark comedy, "World's Greatest Dad."

And they had to take a break.

Seriously.

Watch Robin improv the waxing slave labor ("Nobody knows ... I've been working on Mr. Williams' front for two years! What we get from you we can make a sweater") it took to get him hairless for the film's cathartic finale, that was actually his idea.

"At the end, he's kind of shedding everything," Robin says at the film's press junket at the Four Seasons. He told Bob, "Maybe I should go full. And that's how we work. ... It wasn't done for a laugh. It's cathartic at that point, he's going full-tilt breakdown."

He didn't take painkillers for the long waxing. But Bob says he could have used some after shooting Robin's "hog" all day.

"That was not a Dirk Diggler special effect," Bob insists. Robin says his first nude scene was in "The Fisher King" when he was nude in Central Park. But he explains that "it was a cold night."

Robin jokingly compares the large shadow he cast to a boom mike after which Bob says: "I don't understand why you're insecure. If I was you, I'd be way more confident."

But he did keep his bi-color socks on in the nude scene. And you have to hear Robin explain why.

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Video: Elizabeth Snead