Prince George is also a big fan of The Lion King and the Lego movies

He may be the future king, but to those who know him, Prince George is simply a young boy learning about the world.

“He’s a jolly little person and inquisitive,” a family friend says in this week’s issue of PEOPLE.

And like many 6-year-old boys, he is “full of beans,” the friend adds, using a British expression that sums up his lively spirit.

George, who is a big fan of The Lion King, as well as the Lego movies, has been able to expend some of that energy during an idyllic summer vacation on the island of Mustique with his family. One of his latest birthday portraits — shot by proud mom Kate Middleton — was taken during their family vacation, insiders say. It was used alongside a couple of toothy photos of the giggling soccer fan in his England jersey at home in Kensington Palace.

After his summer vacation wraps, he will help welcome his sister Princess Charlotte, 4, to his school at Thomas’s Battersea, where George has enjoyed learning about space and taken ballet lessons.

Prince George
| Credit: The Duchess of Cambridge

But he still has the rest of the summer to enjoy, and much of it will likely be spent dashing around outside, which his parents support. Earlier this year, Kate, 37, revealed she likes to encourage George, Charlotte, and 1-year-old Prince Louis to spend time outside “rain or shine,” believing “it encourages creativity, confidence.”

“Even a short amount of time — 10-15 minutes outside — makes a huge difference to both physical well-being but also to our mental well-being,” she recently told CBBC’s Blue Peter.

Prince George
| Credit: The Duchess of Cambridge

George has been putting that into practice as he enjoys the perks of a royal summer of fun. In addition to watching their dad Prince William take part in a charity polo match, George and Charlotte have enjoyed a day out at a local country village fair with grandparents Carole and Michael Middleton.

“They were so cute, and Charlotte particularly was very friendly, politely saying hello to other children. George was running around, exactly like all the other children,“ a local said of the family outing.