The 62-year-old slammed Winner for making her take her clothes off during a casting session at the start of her career in 1964.
She told Channel 4's Richard and Judy: "I was mortified and incredibly angry. I thought it was insulting and sexist, and I don't think any actress should be treated like that - like a piece of meat - at all.
"Even if they hadn't done the kind of work that I've done, it was incredibly insulting. I was so angry, I was so angry - I still am."
Winner, 72, claimed that Mirren's agent Margaret Johnson had asked him to tell the actress that she had to wear a bra because of her "enormous sagging boobs".
In an interview with the Daily Express, he said: "[Margaret] rang me and said she had photographs of Helen in which she had these enormous sagging boobs. She thought the photographs wouldn't help her get work."
He admitted that he had told her to stand up, but could not remember asking her to turn around and would not have been serious if he had made the request.
Winner - now a restaurant critic - recalled: "I can see it now. She was wearing a peasant blouse and a skirt in the photographs - with enormous bosoms which were sagging a bit even though she was young. I was only doing what the agent asked me - and for this I get reviled!"
He added: "Helen's a lovely person, she's a great actress and I'm a huge fan, but her memory of that moment is a little flawed."
> Mirren: "I am a nudist at heart"