Camila Cabello admitted she stole something from Kensington Palace during her visit last month.

The "Living Proof" singer made the shocking confession during an interview with BBC Radio 1, jokingly telling host Greg James she couldn't sleep because of her secret. James explained that he and Cabello saw each other at the Teen Heroes event and right before meeting Prince William and Kate Middleton, he dared her to steal a pencil.

“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',” he said before the pop star said he "triple doggy dared" her.

“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,” Cabello explained. "I was like 'oh my god' and I put it in my mom's purse and my mom 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.'"

"So I still have it, I'm sorry William and I'm sorry Kate," she added. "Honestly I'm just so happy to get it off my chest now because I haven't been able to sleep for the past 3 weeks."

The interview was later posted to the Radio One's social media, which prompted the Duke and Duchess of Cambridge to respond to Cabello's admission through Kensington Palace's official Twitter account.

Check out Cabello's interview and the royal reaction, below: