Robin Williams used to grope his Mork & Mindy co-star Pam Dawber as his madcap sense of humor crossed the line into sexual harassment, a new book reveals.
In the upcoming biography of the comedian, Robin, by New York Times journalist Dave Itzkoff, Dawber, 66, tells how the actor repeatedly grabbed her bottom and breasts and took off his clothes in front of her during the four-year run of the show, The Daily Mail reports.
Williams would also wrestle her down and break wind on her, and once "goosed" an elderly actress playing her grandmother by putting a cane between her buttocks, she disclosed.
But the actress, who played Mindy alongside Williams's Mork, admits that she never took offence because the comedian was so charming.
She described filming the show as "so much fun" and remarked: "It was the Seventies, after all."
The show's director Howard Storm also contended that there was "nothing lascivious about it, in his mind, it was just Robin being Robin".
However, the revelations about Williams, one of the most adored comics of all time, could cause consternation for some of his fans and those of the show which ran from 1978 to 1982.
Dawber's unfazed reaction may surprise some too as it comes amid the MeToo movement, when victims of sexual harassment are encouraged to speak out.
Itzkoff interviewed Dawber for the book - set to be released in May and published by Henry Holt. It is the most thorough account of the comic's life since his death by suicide in 2014.
Williams' death came after he was diagnosed with Parkinson's. The autopsy on his body revealed he also had Lewy bodies, a nerve condition which causes dementia.
The TV sitcom made a star of Williams and kicked off his Hollywood career that would include films like Mrs Doubtfire and Dead Poets Society, which made him one of the most famous comics on the planet.
In the show, a spin-off of the television hit Happy Days, he played an alien who comes to Earth from the planet Ork and moves in with a roommate, Mindy.
Dawber, who played a human who would eventually become Mork's wife, gave Williams a springboard for his wild, offbeat humour.
Speaking to Itzkoff, Dawber said Williams was "such a nice person" and had a "gigantic heart," adding that they became close and she became the big sister that he never had.
"I really loved Robin and Robin really loved me. We just clicked," she said.
But on the set Williams did things that went beyond those which a brother and sister would do to each other, ranging from crass behavior, to sitting and farting on Dawber despite her protestations.
Williams, however, also caused tensions on set with his constant improvisations which led some to think there was no script, a myth he perpetuated.
Itzkoff writes that many of these additions were sexual and directed at the women in the cast, such as when he goosed the actress who played Mindy's grandmother with a cane.
Storm said: 'I'm standing there watching this and I'm thinking, "oh my god" and I just laughed. I thought she was going to turn and say: "How dare you stick a cane in a woman's a**?" That sweet old lady.
"There was nothing lascivious about it, in his mind. It was just Robin being Robin, and he thought it would be funny. He could get away with murder."
Other times Williams would grab Dawber's bottom or her breasts simply because he was "bored".
"He'd be doing a paragraph and in the middle of it he would just turn and grab her a**. Or grab a breast. And we'd start again. I'd say, 'Robin, there's nothing in the script that says you grab Pam's a**.' And he'd say: 'Oh, ok'," Storm added.
Garry Marshall, the producer of the show, said: "He would take all his clothes off, he would be standing there totally naked and she was trying to act. His aim in life was to make Pam Dawber blush."
But Dawber remained unfazed, she admits: "I had the grossest things done to me - by him. And I never took offence. I mean I was flashed, humped, bumped, grabbed. I think he probably did it to a lot of people...but it was so much fun.
"Somehow he had that magic. If you put it on paper you would be appalled. But somehow he had this guileless little thing that he would do - those sparkly eyes. He'd look at you, really playful, like a puppy, all of a sudden. And then he'd grab your t*ts and then run away. And somehow he could get away with it. It was the Seventies, after all."
Mork & Mindy changed Williams's life incalculably and by the time it finished in 1982 he had gone from never having had a gig that lasted more than three weeks to a national star.