Helen Mirren reprises her role as Her Royal Majesty the Queen -- this time in stage production The Audience, saying she's 'terrified' about the role and was determined to turn it down.

LONDON, ENGLAND, UNITED KINGDOM  (ITN) -  Dame Helen Mirren has admitted that initially she had doubts about once more playing the Queen on the London stage because "as an actor you want to go forward."

But the hardest thing about her role was, she said, matching up to the real thing.

"The ultimate challenge is that you can never ever be as good as the original," she said.

The play imagines a series ofimportant meetings between the Queen and the 12 Prime Ministers she has met in private on a weekly basis, from Winston Churchill to current British premier David Cameron.

The opening press night for the play is on Tuesday (March 5)