When Prince George was invited to a young girl’s sixth birthday he had to politely decline.

The nine-year-old Prince was invited to an anonymous girl’s sixth birthday party over the school holidays.

However, the Prince had to politely decline and a beautiful letter was written by his mother the Duchess of Cambridge and sent to the young girl apologising for not being able to attend.

“The Duke and Duchess of Cambridge have asked me to thank you for your letter, in which you invite Prince George to your 6th Birthday party,” the letter read.

“I am sorry that it took so long to reply.

“Their Royal Highnesses were extremely grateful for your kind invitation. Having given careful consideration to the possibilities, however, I very much regret that Their Royal Highnesses reluctantly feel they have to decline.

“The Duke and Duchess of Cambridge were immensely touched that you should take the trouble to write as you did to their son, Prince George.

“It really was most thoughtful of you and Their Royal Highnesses have asked me to send you their warmest thanks and best wishes.

“Nevertheless, I hope you enjoy your birthday.”

The eldest child of Prince William and Duchess Kate Middleton only recently celebrated his birthday on July 22.

In honour of his birthday, Kensington Palace released an adorable portrait of the future king on holiday in the UK earlier this year.

“George is turning 9!” the caption simply read with a cake and balloon emoji.

The image shows a huge grin from the young prince as he enjoys a holiday at Norfolk with his family.

The photo was taken by the Duchess who has regularly been sharing snaps of her family as they celebrate milestones.

Prince George was born on July 22, 2013 at the Lindo Wing of St Mary’s Hospital in London and made his first appearance as a day old baby in his mother’s arms as she left the hospital.

Images: Instagram/Getty Images

This article first appeared on OverSixty.