The Prince and Princess of Wales have released a photograph of eldest son George to mark his 10th birthday.

The photograph, taken in Windsor earlier in July by Millie Pilkington, captures him smiling at the camera as he sits on stone steps, wearing a checked shirt with the sleeves rolled up, chino trousers and smart brown shoes.

George is the eldest grandson of the King and is second in line to the throne, behind his father.

With siblings Princess Charlotte and Prince Louis, George lives with parents Prince William and wife Catherine on the King’s Windsor estate. He played a starring role in his grandfather’s coronation in May, as a page of honour.

-with AAP