Happy birthday to HRH Prince George! On Monday, the future King turned six, and while George and his family are enjoying a sun-soaked, private summer holiday in Mustique, the Duke and Duchess of Cambridge delighted fans by sharing three new photos of their firstborn. William and Kate chose to release two portraits that were taken earlier this summer in the garden of their London home, Kensington Palace, as well as this sweet snap from their holiday on the private Caribbean island. In the photo, George smiles tentatively at the camera, looking beach-ready in a pair of blue swim shorts by Sunuva and a teal polo shirt. In honour of George's birthday, we're taking a look at other members of the royal family aged six…
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Prince Charles
Doesn't George look nearly identical to his granddad, Grandpa Wales?
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Prince William
How sweet does George's father, Prince William, look back in 1988, standing next to his mum Princess Diana?
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Princess Diana
George's grandmother Princess Diana is pictured back in 1969 when she was a young Lady Diana Spencer.
The Queen
Even as a young child, Her Majesty looked prim and proper, wearing a pair of elegant white gloves and holding onto a small handbag. The Queen was on holiday in Abergeldie Castle, Scotland in 1933.
Prince Harry
George's uncle Prince Harry looks very smart in his mini suit!
Princess Beatrice
How sweet does Princess Beatrice look as a six-year-old, accompanying her mum Sarah, Duchess of York to a Christmas carol concert at St Luke's Church, London in 1994?
Princess Eugenie
As does her younger sister Eugenie! The little Princess is pictured here at Wentworth, watching her dad Prince Andrew play golf.
Zara Phillips
Back at her old stomping ground, Zara, aged six, enjoys a day at the Windsor Horse Trials.
Peter Phillips
Her older brother Peter Phillips had the blondest hair as a youngster.
Prince Andrew
A six-year-old Prince Andrew plays in the grounds of Buckingham Palace with his little brother Prince Edward.
Prince Edward
Pictured a bit older in his sixth year, Edward celebrates the 70th birthday of his grandma, the Queen Mother.
Lady Louise Windsor
Prince Edward and the Countess of Wessex's firstborn, Lady Louise, looks adorable as a six-year-old. The little girl was joining members of the family on a ten-day cruise in Scotland to celebrate the 60th birthday of Princess Anne and the 50th birthday of Prince Andrew in 2010.
James, Viscount Severn
Louise's younger brother James made a sweet appearance at the London 2012 Paralympic Games at Eton Dorney.
Savannah Phillips
Six-year-old Savannah, the daughter of Peter and Autumn Phillips, plays on a climbing wall at the Royal Windsor Horse Show.
Isla Phillips
Her sister Isla was one cool six-year-old, rocking a jumpsuit while playing on a bouncy slide at the Festival of British Eventing.