The actress, who won acclaim and an Oscar for her portrayal of Queen Elizabeth II in Peter Morgan and Stephen Frears' 2006 film The Queen, will don the royal attire and tiara again for a new West End play, called The Audience, next year (13).
Director Stephen Daldry has now confirmed he'll begin staging the production in February (13), and admits he was surprised when Mirren agreed to tackle the role for a second time.
He tells the London Evening Standard, "It's (a) testament to Peter's script that she wants to reprise a role she is very well known and celebrated for."
Britain's Daily Mail reports Mirren will fly to London from the set of the Red sequel in Canada next week (beg24Sep12) to meet with Daldry and Morgan for a second read-through of the play.
The actress will portray the Queen from her mid-20s to the current day in the project, which chronicles the monarch's weekly meetings with the U.K. Prime Ministers who served under her.
Daldry adds, "It's an astonishing journey from when she was only 25 years old to the Elizabeth she is today."
And Mirren accepts the role will be "a challenge" - because she'll have to alter her voice as her royal character ages.
She explains, "Her voice has changed, and I can use that - she had a terribly posh voice when she was young."
The actress attended a first reading of the play in June (12), when she was determined to turn the project down - but had a change of heart.
She recalls, "I was thinking, 'You shouldn’t really be doing this, Helen. I don’t think it’s right. And the thought of doing a play - you can’t go anywhere for six months!"
But the prospect of re-teaming with Morgan and working with Daldry proved too much for her.
The Audience will begin previews at London's Gielgud Theatre from 15 February (13).