Prince George and Princess Charlotte already know there’s nothing like the bond between brother and sister.
Whether they’re stealing the show at royal weddings or casually kicking around a soccer ball while dad Prince William plays polo, the royal siblings’ relationship is strengthened by their unique upbringing — after all, most kids don’t call Queen Elizabeth “Gan Gan.”
“They are close in age, and they spend so much time together,” an insider tells PEOPLE in this week’s cover story. “Playdates can be tricky, so they learn to lean on each other.”
That’s not to say the pair aren’t without their differences — Prince George, 6, is “more reserved” while Princess Charlotte, 4, is “more outgoing.” In addition, they’ll be prepared for very different roles with George third in line to be monarch (after grandfather Prince Charles and dad Prince William).
The children’s varying personalities were on display at their parents’ charity sailing race last week, with Charlotte playfully sticking out her tongue at one point.
“Kate just handled it wonderfully,” says a longtime royal observer. “She just laughed, and it was really lovely to see. For once you looked at them and thought, ‘They’re a family,’ rather than ‘the royal family.’ ”
Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!
While Prince Louis, 1, is quickly catching up to his older siblings — Kate has said she’s “running after him all the time” — George and Charlotte will soon share more time together. In just a few weeks, the little princess will join her big brother at Thomas’s Battersea, a $23,000-per-year private school some three miles from the family’s Kensington Palace home.
“She can’t wait to be with George at big school,” says the insider. “She is so excited about it all.”