Dame Helen Mirren, 76, returns to screens nationwide today as she plays Queen Elizabeth II in ‘The Queen’ on ITV3. The broadcast of the British biographical drama is perfectly timed, with Her Majesty’s forthcoming Platinum Jubilee to mark her 70 years of reign in less than a fortnight. Dame Helen portrays the monarch in 1997 as the royal family and the nation struggled to come to terms with the tragic death of Diana, Princess of Wales, who was married to the Queen’s son and heir apparent, Prince Charles.

The veteran English actress’ Oscar-winning performance was acclaimed by critics around the world.

Dame Helen captured the Queen as an iron monarch who proved resilient to pressure from Tony Blair to hold a public funeral for Diana and to address public grief over her death in a car crash in Paris .

The former Labor Prime Minister, who dubbed Diana “the people’s princess”, is played by Michael Sheen.

In 2007, Dame Helen won the Oscar for Best Performance by an Actress in a Leading Role for ‘The Queen’.

But just a year after being celebrated for her majestic performance, the star admitted she used to ‘love’ snorting cocaine as she was interviewed by former newspaper editor Piers Morgan for GQ magazine.

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The actress has revealed how she quit the Class A substance after learning that Nazi war criminal Klaus Barbie had profited from the sale of the illegal stimulant while avoiding capture in South America.

Speaking in 2008, she told Mr Morgan: ‘I loved the coke. I never did much, just a little at parties.

“But what ended me was when they caught Klaus Barbie, the Lyon butcher, in the early 80s.

“He was hiding out in South America and living off the proceeds of being a cocaine baron.

“And I read this in the paper, and all the cards fell into place and I saw how my little puff of cocaine at a party had an absolute direct route to this horrible fucking man in America from South.”

She explained that a friend reassured her as she started taking the psychedelic: “I don’t know how people can take it every time.

“I had a wonderful time on it – it was wonderful, partly because my good friend came up to me just as the world was refracting and said, ‘Don’t worry Hel, it’s okay go. Let yourself go and enjoy it and you’ll be fine,” and I did.

“He kind of saved me and I had a fantastic time. But it’s enough, it’s enough.”

In her interview with GQ, the actress also admitted to smoking weed, but claimed cannabis left her feeling depressed.

She said, “I hated it. Dope has always made me feel miserable, paranoid and unhappy.

“And I woke up one day and thought, ‘No more of that, thank you’.”

‘The Queen’ airs on ITV3 today from 7pm.