A spokeswoman for the royal couple had no comment.
While her name has not been reported, the new staff member was hired as a successor to Jessie Webb, who was Kate and William's initial helper around the nursery.
And her timing is perfect. She assumes the job before the family's three-week tour of New Zealand and Australia in April, by which time she and George should be well accustomed to each another.
Since arriving in the U.K. from Spain a couple of decades ago, "She has worked for other high-profile families," a friend told Hello! magazine. "And it was from there that the Cambridges heard of her and hired her."
The friend added, "She is not married and doesn't have a boyfriend, as her life is totally dedicated to the family she is working with. She is known for being totally professional – married to the job."
But the new nanny is not looking after George this week. He is with his grandparents, Carole and Michael Middleton, while William and Kate enjoy a sunny break in the Maldives.