As the actress playing the Queenin the Netflix series The Crown, Olivia Colman has to channel to monarch's sense of duty and protocol.
But while promoting the series in an interview for theSunday Times, she caused a stir by becoming the latest celebrity to admit to being part of misbehaviour at Buckingham Palace - confessing that her husband stole a souvenir.
Buckingham Palace declined to comment, but the palace previously told the BBC that the vast majority of guests do not take anything.
"We get nearly 50,000 visitors a year and if they all took souvenirs there wouldn't be much left," a spokeswoman said after an earlier celebrity incident.
Denise Van Outen
The TV presenter apologised after admitting to "borrowing" an ashtray and a tissue box holder from the palace in 1998.
She told viewers of Channel 4's The Big Breakfast, which she presented at the time, that it was "just a bit of fun".
She said she sent them back with a gift - a stuffed camel with a note saying: "Sorry, Ma'am. I didn't mean to give you the hump."
The Spice Girls singer revealed on ITV2'sCelebrity Juicethat she pinched a sign for the ladies' loos when she was invited to the palace to perform for the Queen.
Her light-fingered moment took place during the concert for the Golden Jubilee in 2002.
light-fingered [ˌlaɪt ˈfɪŋɡəd]：adj.手指灵巧的；善于扒窃的皮尔斯·摩根（资料图）
The Good Morning Britainpresenter admits to being a serial offender in the loos of the rich and famous.
He said he once had a collection of toilet paper swiped from celebrity homes, with Simon Cowell's toilet roll ("black and monogrammed") now displayed next to the Queen's.
But his nerve failed in the White House when Barack Obama was president. "I feared I would find myself in jail," he told the Mailon Sundayin 2011.
The Oscar-winning actress told theSunday Timesthat her husband had swiped a toilet roll when the couple were attending a charity event.
"My husband stole some loo roll just to say we got it from Buckingham Palace," she said.
It's not quite clear how complicit Colman herself was in the crime - we may need to put Broadchurch's finest detective Ellie Miller on the case to learn the full truth.
A former press spokesman for the Queen, Dickie Arbiter says honest visitors to Buckingham Palace who leave without stealing a souvenir are not missing out.
"It's quite ridiculous. The toilet paper doesn't have 'Buckingham Palace' on it, it's just plain white paper like everyone else has," he says.
And he questions whether an ashtray could have been taken from the palace in 1998, saying that it had been a non-smoking zone since well before Denise Van Outen's confession.
There are very few opportunities for souvenir hunters, he says. Cutlery is not embossed with a palace design and visitors to the palace are usually given napkins with their canapes rather than plates.
But he suggests celebrity thieves are more in search of publicity than mementos.
"It's not that they're taking anything of value. It's just so they can say, I've stolen a loo roll from Buckingham Palace," he said.
"Go to Poundland and buy yourself a pack of nine."
John Lennon once claimed that the Fab Four smoked cannabis in the toilets before collecting their MBEs in 1965.
But fellow Beatle George Harrison later disputed this account, saying that the band just went to the loo for an ordinary cigarette "because we were so nervous".
Buckingham Palace was just one of the high-profile locations in which the comedian and writer - a friend of the Prince of Wales - says he took cocaine.
In his memoir More Fool Me, he says he took the drug in several other royal palaces, as well as the House of Lords, House of Commons and BBC Television Centre.
He wrote: "I have brought, you might say, gorgeous palaces, noble properties and elegant honest establishments into squalid disrepute."