She has landed the role of a lifetime that would naturally make anybody feel a bit potty about the monarchy.
But Olivia Colman, 45, has said she has become so "obsessed" with the Queen while playing her in The Crown that she has even stolen some royal toilet paper.
The actress said she met the Queen and Prince William since landing the lead role in the Netflix show and when she visited Buckingham Palace she wanted a little memento.
She told Sunday Times Culture: "I've met the Queen in a line-up at the BFI, and the lovely Prince William at a charity do at the palace. I was very uncool, and he was charming.
"He said, 'I know what you're doing here.'
"I asked, 'Do you watch it?'
"He said, 'No I don't'."
She added: "Then my husband stole some loo roll just to say we got it from Buckingham Palace."
Colman, who won an Oscar for her portrayal of Queen Anne in The Favourite earlier this year, admitted she has become a "lefty monarchist" since replacing Claire Foy as the Queen on screen.
"The thing is, I was always a republican, but I have to say I've become completely obsessed with the Queen," she said. "Who could stick with something like that for so long, quietly and with such humility?
"We know she loves to escape to the Highlands, she probably goes crazy up there – she must release in some way, running around naked, screaming and pulling her hair out."
The new series of The Crown starts next month.