A source told People magazine that George, 6, and Charlotte, 4, have grown especially close, because play dates with outsiders can sometimes be ‘tricky.’
The eldest Cambridge children, who are close in age, have been spotted playing together on recent outings, kicking a football around at a charity polo match in July, and dipping their toes in show stream in May.
Charlotte is also said to be ‘so excited’ to join her big brother at ‘big school’ Thomas Battersea in the autumn, when it’s likely the siblings will grow even closer.
While little brother Prince Louis, 16 months, is a full three years younger than Charlotte and five years younger than George, his older siblings were born just 22 months apart.
An insider revealed: ‘They are close in age, and they spend so much time together. Playdates [with outsiders] can be tricky, so they learn to lean on each other.’
On recent outings, the children have appeared incredibly close, and were seen mucking about as their parents took part in a yacht race last week.
And while Prince William played in a polo match with their uncle Prince Harry in July, Prince George and Charlotte were seen chasing around after a football together.
When Kate Middleton revealed her Chelsea flower show garden earlier this summer, the older children also appeared keen to play with one another, opting to sit together and dip their toes into a stream.
It’s likely their bond will only grow stronger in the autumn, when Charlotte joins her big brother at his school, Thomas Battersea.
The insider said that the little princess was over the moon to be attending ‘big school’ with her brother.
They revealed: ‘Charlotte can’t wait to be with George at big school. She is so excited about it all.’
The sibling’s close bond comes despite their difference in personalities, with Prince George often appearing more reserved and quiet.
Meanwhile Princess Charlotte appears quite outgoing and is often playful with awaiting photographers.
At the weekend she poked her tongue out at those watching, and at brother Louis’ christening last year she charmed global media when she told paparazzi that they weren’t coming in.