The Queen star was committed to relax with her sister Kate when the phone rang and Mamet asked her to give up the rest of her vacation and fly to New York.
Mirren recalls, "I was determined not to work for the next three months or so, because I was very tired from working so much and just wanted to rest... (but) it was the dream job. I would have died to work with Al Pacino... My heart was dropping and I thought, 'Oh my God, I'm going to have to do this'.
"I said, 'I need time to prepare. I'm playing an American, and I'm not terribly good at accents, so I need to have a week to prepare'. They gave me exactly a week, but I had to fly out the next day and do it in New York."
And she tells Success magazine, "I was terrified of working with Al (and) terrified of working on Mamet's type of text because he's such a brilliant writer. I've watched many of his plays and wondered, 'How did the actors learn that?' It's so interwoven and dense, and you know that kind of writing is not to be improvised. You have to learn every word, and the rhythm of every interjection. So I was absolutely contemplating shooting myself."
But the gamble paid off - Mirren, Pacino and Mamet all won acclaim for their roles in the court room drama, which aired in America earlier this year (13).