"I loved coke. I never did a lot, just a little bit at parties," Mirren was quoted as telling the magazine in an interview, which was made available to the media Monday. "But what ended it for me was when they caught (Nazi war criminal) Klaus Barbie, the Butcher of Lyon, in the early 80s. He was hiding in South America and living off the proceeds of being a cocaine baron.
"And I read that in the paper, and all the cards fell into place, and I saw how my little sniff of cocaine at a party had an absolute direct route to this ... horrible man in South America," she was quoted as saying.
Mirren also reportedly said she used to steal during what she described as a "very poor" youth.
"I needed to shoplift for food," she reportedly said, adding that while she enjoyed "the accoutrements of movie star life" she still had frugal instincts, cutting her own hair and wearing dollar-store glasses.
Mirren said she was not a royalist but had become a fan of Queen Elizabeth II since playing her in "The Queen."
"It's a miracle she's never gone mad," Mirren was quoted as saying. "She is a remarkable person, who has achieved an amazing thing with a life she neither chose for herself, nor particularly wanted."
Mirren's interview is carried in the British edition of GQ, which goes on sale Thursday.