Cabello was chatting with Greg James on BBC Radio 1 when she blurted out, as seen in the clip below: “Don’t tell anybody what my mother and I did.”
That prompted a full account of how James dared her to steal said pencil at an event in the palace last month to honor teen heroes.
“You can’t not do a triple doggy dare, so I did it,” Cabello said.
Cabello chided the DJ for then alerting the palace staff and described how she stashed the pencil in her mother’s purse and ignored her pleas to put it back.
“I still have it,” the “Havana” singer said. “I’m sorry, William, and I’m sorry, Kate.”
The Duke and Duchess of Cambridge apparently got wind of the interview. Their Twitter account replied with a suspicious-eyes emoji, playfully admonishing Cabello.
Radio host James generated headlines this week when he revealed that the royal couple confronted him for joking about their daughter Charlotte shaking hands with the teacher on the first day of school. But he said they are on good terms.