When one accepts an invitation to meet the royals at their official residence, it's expected that you'd be on your best behaviour.
So royal fans have been left a little shocked, after US pop star Camila Cabello admitted that during a recent visit to Kensington Palace for an awards ceremony, she succumbed to a dare and stole a piece of royal property from the Cambridge family.
Camila, 22, revealed she was a guest of Duchess Catherine and Prince William at Kensington Palace last month, and joined BBC Radio One DJ Greg James and finalists of the radio station's Teen Heroes of 2019 Awards at the Palace.
Speaking to Greg on BBC Radio One this week, Camila revealed that the DJ dared her to steal something from the royals.
"We're in Kensington Palace for the Teen Hero Awards. We were about to meet William and Kate, and I said 'You've got to steal something, steal that pencil'," Greg said.
Camila responded: "I was like 'You triple doggy dare me?' You can't not do a triple doggy dare. If there's anything I've learnt in my life it's that, so I did it."
So Camila swiped a pencil and put it in her Mum's purse.
But the former X-Factor star said she was soon outed by her friend to a Palace staffer.
"And then [Greg], to one of the Palace people, called me out on it and you were like 'She stole a pencil', and I was like 'Oh my God'," Camila said.
"And I put it in my mum's purse and my mum was like 'No we have to give it back, we have to give back the pencil'.
"And I was like 'No, he triple doggy dared me I have to take the pencil', so I still have it."
She then issued an on-air apology to the royals, saying: "So I'm sorry William and I'm sorry Kate."
But it was the Palace's response to a tweet from the BBC, featuring a video of Camila and Greg recounting the story, has been met with both praise and amusement from royal fans.
"I am sorry William and I am sorry Kate @KensingtonRoyal - @GregJames may have got @Camila_Cabello into a bit of trouble at the Palace," BBC Radio 1 tweeted, alongside the video.
Hilariously, the official Kensington Palace Twitter account responded with the wide-eyed emoji.
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Royal fans couldn't get enough of Kensington Palace's response, taking to Twitter to voice their opinions.
"Love this reply @KensingtonRoyal," one fan wrote, while another wrote, "THE SHADE"
"One of the best moments o my Twitter existence ever", another person wrote, while a fourth said, "Brilliant response @KensingtonPalace #KensingtonPalace."