A Kensington Palace spokesperson said the Duke and Duchess were “delighted” to share the new image on the occasion of George’s birthday.
“The photo was taken earlier this month while on holiday in the UK by the Duchess,” they said.
It is the second portrait of the Duchess to be published within a month, after the Duchess of Cornwall commissioned her to photograph her for the cover of Country Life magazine.
A sharp amateur photographershe regularly publishes photos she has taken of her children to celebrate their birthdays and is a patron of the Royal Photographic Society.
The Cambridges are said to have left for a summer break shortly after the kids left school.
Upon their return, they begin a new chapter with a move to Windsor and a new school for all three children starting together in September.
For the first time, Prince Louis, four, will join Prince George, nine, and Princess Charlotte, seven, as they don their uniforms to start a new school year.
Moving to Adelaide Cottage
The family moves from Kensington Palace to Adelaide Cottage, a four bedroom property just a stone’s throw from Windsor Castle.
The move brings them closer to the Duchess’ family in Bucklebury, Berkshire, but also within walking distance of the Queen, 96.
It will allow the duke to maintain close contact with his grandmother and her staff, who are largely based in the castle.
The expansive Windsor Estate gives children more space to play, ride horses and walk their dogs in privacy.
The Duke and Duchess will also be there to do the school career and immerse themselves in the busy pre-school life, with its many sports and social activities.
The young royal and future king turns nine on Friday and is reported to start later this year at Lambrook School, in Ascot, near Windsor Castle.