The Havana singer was chatting with Radio 1 presenter about a recent visit tot he palace when she blurted out: “Don’t tell anybody what my mother and I did.”
Her comment prompted a full account of how Greg James dared her to steal said pencil at an event in the palace last month to honour teen heroes.
“You can’t not do a triple doggy dare, so I did it,” Camila told listeners.
Camila 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,” she added. “I’m sorry, William, and I’m sorry, Kate.”
The Duke and Duchess of Cambridge apparently got wind of the interview, and shortly afterwards, their Twitter account replied with a suspicious-eyes emoji, playfully admonishing Camila.
Greg James generated headlines this week when he revealed that the royal couple had confronted him for joking about their daughter Charlotte shaking hands with the teacher on the first day of school.
“They said: ‘We were listening on the morning of little Charlotte’s first day, and we want to talk to you about the handshaking thing’,” he explained. ”“I went: ‘Oh God, no!’
“They’d heard me saying, ’This school was so posh they had to shake hands with their teacher every day. They were not like that in my day. You were pleased if you got a smile.”
However, he has maintained that he is on good terms with the Duke and Duchess.