The young prince has been captured looking happy and carefree in the four images taken earlier this month at the royal couple’s Norfolk home, and published on the day George turns three.
William and Kate have also thanked well-wishers for the messages of support they have received marking their eldest child’s special day.
A barefoot George plays on a swing in two of the images, in another he is crouching on a rug while holding an ice cream under the nose of family dog Lupo, and in the final picture he is shown strolling through the grounds of Anmer Hall.
A Kensington Palace spokesman said: “The Duke and Duchess hope that people will enjoy seeing these new photographs. They would like to thank everyone for all the lovely messages they have received as Prince George celebrates his third birthday.’’
The images were taken in mid-July by photographer Matt Porteous, a director of Studio M, an award-winning creative studio which specialises in portrait and commercial photography and film, and is based on the island of Jersey.
He said: “I really enjoyed the opportunity to take these photographs of Prince George. It was a very relaxed and enjoyable atmosphere. I’m honoured that they have decided to share these images with the public to mark his third birthday.’’
George is shown in three of the pictures wearing a striped blue T-shirt and dark blue shorts - which are likely to sell out when identified by royal-watchers on social media.
In the fourth picture, where he has been captured walking, the young prince wears a navy and cream striped cotton sweater by Pepa & Company, with the image of a whale on the front, beige shorts and dark canvas shoes by Hampton Classics.
The swing George is seen standing on in one picture, and seated in another, is clearly carved with the names of his parents “William & Catherine’’.
It may be a lovers’ swing sometimes given as a wedding gift, with the couple’s name carved into the front and the date of their marriage on the reverse.
In the picture showing George with the family dog, he can be seen holding a partially eaten ice cream close to Lupo’s mouth.
The cocker spaniel is a strain of the breed traditionally used as a gundog - and they can cause havoc around the house.
An RSPCA spokesman said: “It is lovely that Prince George is trying to help keep his family dog, Lupo, cool in these high temperatures.
“We would advise people to be cautious when giving their dogs food meant for human consumption as some items, like chocolate, can be highly toxic to dogs and dairy items can be difficult for them to digest.
“Instead of ice cream we would suggest making an ice lolly from pet-friendly ingredients. Making these can be really fun for children and the end product is both safe and enjoyable for dogs.”