Helen Mirren wrote a letter to Queen Elizabeth II before she started work on The Queen.
The British actress portrayed the monarch in the 2006 biographical drama, which delved into the death of Diana, Princess of Wales in 1997.
Mirren, who won an Academy Award for her performance, revealed in an interview for the latest issue of Radio Times that she penned an honest note to The Queen prior to production.
"I realised we were investigating a profoundly painful part of her life, so I wrote to her," she recalled. "How do you write to your queen? Was it Madam, or Your Highness, or Your Majesty? I said, 'We are doing this film. We are investigating a very difficult time in your life. I hope it's not too awful for you.' I can't remember how I put it. I just said that in my research I found myself with a growing respect for her, and I just wanted to say that."
Mirren went on to explain that The Queen didn't respond directly to her.
"She didn't write back, of course, but her secretary did. You know, 'Yours sincerely, da di da di da,' on behalf of the Queen. I was very relieved subsequently that I had written that letter," the 76-year-old added.