Camila Cabello has some sticky fingers but now is regretting her latest grab.

The 22-year-old singer appeared on BBC 1 Radio's "Breakfast with Greg James" for an interview Tuesday and admitted she took something small from Kensington Palace during a visit in October.

"Don't tell anybody what my mother and I did," she warned James during the radio show.

PRINCE WILLIAM, KATE MIDDLETON SPOKE WITH RADIO HOST AFTER HE MOCKED PRINCESS CHARLOTTE

"We were at Kensington Palace... we were about to meet [Prince] William and Kate [Middleton] and I said, '[You] gotta steal something. Steal something... steal that pencil," he explained.

Camila confessed: “And I was like, you triple-doggy-dare me? And you can’t not do a triple-doggy-dare. If there’s anything I’ve learned in my life, it’s that. So I did it."

"I did," James confirmed. "I triple doggy dared you."

But then James ratted her out to a palace official.

“You, to one of the palace people, called me out on it, and were like, ‘She stole a pencil!’ And 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,’” Cabello continued.

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In the end, she kept the pencil but immediately apologized to the royal couple on the air. She told them: “So I’m sorry. I still have it. I’m sorry William, and I’m sorry Kate. I honestly couldn't sleep last night. I had to get it off my chest."

William and Kate appeared to have a sense of humor though and replied to the tweet with the side eyes emoji on their official account.

Cabello and James teamed up for the BBC Radio 1 Teen Heroes event at the palace which honors inspirational teens who help others.