Why Prince George doesn't want to play with little sister Princess Charlotte anymore.

At the ripe old age of five, Prince George has a lot on his plate. He’s at school now, don’t you know, and there are lessons to be learned and friends to be made.

The life of the future King of England is busy and so some things have had to take a backseat, one of them being play time with younger sister Princess Charlotte, three.

According to a source who spoke to PEOPLE magazine, George is “very independent now and not as interested in playing with Charlotte all the time.”

But don’t worry, it’s nothing personal.

“They are close,” the source insisted, “but George likes to go off and do this own thing.”

The source also revealed to the magazine some sweet details about the little prince’s personality.

“George takes a little while to warm up,” they said “but once he’s comfortable with you, he’s very chatty and charming.”

Prince George, the eldest child of Prince William and the Duchess of Cambridge Kate Middleton, celebrated his fifth birthday on July 22, an occasion marked with a new royal portrait.

In the photo, George displays a very cheeky grin and cheekiness is obviously a trait he has passed down to this little sister, since Princess Charlotte made a rather ballsy remark to the paparazzi waiting outside Prince Louis’ christening last month.