Kathryn Rossetter, who played alongside the Oscar-winning actor in a 1983 to 1985 Broadway production of "Death of a Salesman," made the allegation in a guest column for The Hollywood Reporter.
All had begun well, Rossetter wrote, after Hoffman helped her get the role, her first on Broadway.
He even introduced her to his wife, she said.
But things quickly turned into "a horrific, demoralizing and abusive experience at the hands (literally) of one of my acting idols."
Once during a performance in Chicago, "I felt his hand up under my slip on the inside of my thighs," the start of abuse that happened "almost every show," she said.
"He kept it up and got more and more aggressive," said the actress, who said Hoffman tried to digitally penetrate her on one occasion.
"Night after night I went home and cried."
"How could the same man who fought to get me the job, who complimented my work, who essentially launched my career, who gave me the benefit of his wisdom as an actor, how could he also be this sexual power abuser?" Rossetter wrote.
"Was I doing something? Was it my fault?"
"Dustin would whisper, 'higher, higher,' trying to get me to move up his pants legs toward his genitals. I didn't do it."
Rossetter said that she considered reporting Hoffman to the actors' union but was dissuaded by others who said she would probably lose her job and her hopes of a career.
The actress later performed in the 1985 TV movie version of "Death of a Salesman," which also starred Hoffman.
A former intern on that set, Anna Graham Hunter, previously accused Hoffman in The Hollywood Reporter of putting his hand on her buttocks and making suggestive comments when she was 17.
The 80-year-old Hoffman, whose numerous film credits include "Tootsie," "Kramer vs. Kramer," "Rain Man" and "All the President's Men," said he did not remember that episode from more than 30 years ago.
He added that he did not believe he had done harm, and that his conversations on the set were typical of those among members of a "family."
An outpouring of sexual assault allegations in the US entertainment, media and political worlds began in October with claims against disgraced movie mogul Harvey Weinstein, who has been accused by more than 100 women of behavior ranging from intimidation to rape.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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