The new nanny, who started with Prince William and Kate Middleton earlier this month, will travel with the royal family to Australia and New Zealand on their upcoming tour. Maria, who is in her mid-30s, will be tasked with looking after seven-month-old Prince George.
Get all the latest news about the tour here
William, 31, and Kate, 32, are said to be "delighted" with Maria's arrival.
According to Kensington Palace, the full-time nanny trained at Norland College, a childcare training college in Bath.
"As an employee of the Royal Household we would ask, please, that Maria's privacy, and that of her family and friends, be respected," added a spokesman for the palace.
"We will not be giving further details on Maria or her employment, except to say that the Duke and Duchess are of course delighted she has chosen to join them."
HELLO! magazine exclusively revealed in issue 1319 that William and Kate had hired a new nanny just before they went on holiday to the Maldives. The royal parents left behind their firstborn in the safe hands of Maria, and Kate's grandmother Carole Middleton, to let the nanny and baby George bond while they were away.
Maria has no doubt been getting to know George's routine and habits. The pair were recently spotted enjoying a stroll in Hyde Park, accompanied by a personal protection officer and more policemen patrolling the grounds.
Prince William's childhood nanny, 71-year-old Jessie Webb, came out of retirement especially to look after George after his July birth. Jessie is said to have been showing Maria the ropes.
As George will be a mere eight-months-old when he makes his first official trip overseas, the young tot will not be making many public appearances but may take the spotlight on a few occasions.
Click here for William and Kate's three-week itinerary.
"One or two engagements across the three weeks have been identified as times when the Duke and Duchess might take Prince George along, too," William's private secretary Miguel Head told a press briefing.
The royal family will be abroad from Monday 7 April to Friday 25 April.