Britain's Prince George, the son of Prince William and his wife Kate, celebrated his third birthday on Friday with his father's office releasing new photographs of the great grandson of Queen Elizabeth.

George, the third-in-line to the British throne, was pictured with the family dog Lupo and playing in the grounds of the country mansion in Norfolk, east England, which belongs to his parents, the Duke and Duchess of Cambridge.

Photographs of the young prince, who attends a local nursery, are hugely in demand with the world's media and William and Kate have been fiercely protective of his privacy, leading to some criticism that too few images of the toddler and his one-year-old sister Princess Charlotte have been released.

"The Duke and Duchess hope that people will enjoy seeing these new photographs," William's office said in a statement. "They would like to thank everyone for all the lovely messages they have received as Prince George celebrates his third birthday."

All images sourced from Reuters