How Prince George Will Celebrate His 10th Birthday (Exclusive)

Royal family expert Katie Nicholl spoke with ET about how Prince William and Kate Middleton's eldest son will ring in his b-day.

How time flies! Prince George will soon be celebrating his 10th birthday.

As the future king prepares to hit double digits, ET spoke with royal expert Katie Nicholl about how George's parents, Prince William and Kate Middleton, plan to ring in his special day on Saturday.

According to Nicholl, the Prince and Princess of Wales "are known to celebrate big birthdays, but they are known to do it below the radar."

"I'm told that this birthday party will be family, of course, close friends, friends from his old school, [and] friends from George's new school, but it's not going to be showy in any way," Nicholl shared. "A lavish party, where there's a huge expense, is just not William and Kate's style."

"She still always bakes the cake, she will be doing a tea party, I'm told there's going to be something of a football theme involved in the celebrations," Nicholl added.

She also explained that the party will either be held at Windsor Castle or, more likely, at the family's home in Norfolk. "There's more space there and of course it's where they're completely protected. So whatever does happen will stay very firmly behind closed doors."

As Prince George gets older, Nicholl says that the young royal seems to be learning to embrace his role in the spotlight more and more, especially when sharing the responsibility with his siblings -- Princess Charlotte, 8, and Prince Louis, 5.

"He seems to enjoy being in the public spotlight far more than he used to," Nicholl shared. "I think he's definitely finding his feet and coming into his own... This is a big birthday for him, it's an important birthday, and he strikes me as someone who is very comfortable in his own skin, and very grateful for the support of Charlotte, particularly."

"You don't often see George without Charlotte. I think they're very much a team, and she plays this important supporting role," she continued. "But I do think we've seen George become perhaps a little less reserved, a little bit more outgoing and certainly thriving from having the support of Charlotte and Louis by his side."

It's important for George to be able to embrace the spotlight, so to speak, because of his future role in the royal family.

"George is absolutely aware of the role that lies ahead of him and he knows that his father will be king next, and after that he will be crowned king, and who knows what the landscape is going to look like? But he's absolutely aware of his destiny."

Which is why his parents are "very anxious not to burden him with that weight and responsibility."

"I think what they're trying to do is raise him with that balance of normality," Nicholl said. "And he does have a surprisingly normal life... they live in a four-bedroom cottage, they don't even have live-in help, because there just isn't the space, and there's a very, very heavy influence from Kate's family, the Middletons. Carol and Mike are very involved with George, Charlotte and Louis."