George and Charlotte - who are older siblings to Prince Louis and children to Prince William and Kate Middleton - are said to occasionally argue over toys and tv shows like most siblings their age, but get along most of the time.
Charlotte joined her older brother at Thomas's Battersea School in September this year, with her mum saying she was "very excited to join her big brother."
Despite his seemingly shy nature, Prince George is a popular pupil amongst his classmates.
Royal insiders told The Daily Mail that the future king has already invited 'a few' of his classmates back to Kensington Palace.
A royal insider has revealed to The Sun that while some of George's friends have accepted invitations to play with the prince, they've also found the dates take a little more planning than usual as everyone who visits the Palace has to be vetted first.
"It is wonderful for them – and their parents – to go to such a beautiful and historic palace and have the run of the place," the insider told the publication.
"But it does involve a bit more planning than a normal play date, as everyone visiting the palace has to be security vetted."
Regardless, Duke and Duchess of Cambridge are said to be "delighted" at how comfortably their oldest child has settled into the school.