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Dressed in coordinating blue ensembles, the royal siblings were the life of the party – which was also attended by local military families – as proud parents Prince William and Princess Kate kept a watchful eye on their little royals.
From balloon popping to bunny petting, here are the seven cutest moments from the royal playdate.
1. Charlotte finds true love in a balloon arch
As soon as her little feet touched the ground, Princess Charlotte had one mission and one mission only: touching as many balloons as possible. The almost 17-month-old began by alternately hitting and hugging the balloons and finally tried to lift up the entire pastel-colored balloon arch. Her enthusiasm was infectious; even big brother George joined her in on the royal balloon inspection.
2. George shows he’s a budding equestrian like his dad
Prince William was bursting with pride as he watched his son sit atop a caramel-and-white colored pony. William and his grandmother Queen Elizabeth are lifelong equestrians, and George is already following in their horseshoe-loving footsteps.
“It was nice to see how down to earth Will and Kate were,” party guest Lisa Gentile, who attended with her 3-year-old niece Hannah, told PEOPLE. “They were playing with their kids just like any other parents.”
3. Charlotte meets Moose
Not one to be outdone by her big brother, Charlotte (a.k.a. the Queen’s mini-me!) took a seat atop Moose, a golden-retriever poodle mix who works as a cancer therapy dog. And she couldn’t seem to get enough of the patient pup!
4. George makes new friends
George’s love for bubbles was certainly a highlight of the day. He even asked other youngsters to join him in a bubble-popping frenzy. “George said, ‘Nice to meet you’ and ‘play bubbles with me,’ ” Luca Berti, whose dad is a marine engineer, told PEOPLE. “George and Charlotte were just like any other kids,” Luca’s dad, Chris Berti, added. “They had the same temperament and the same willingness and openness to meet everyone.”
5. Charlotte has a cuddly moment
Despite the excitement at every corner, the royal siblings took the time to give the black-and-white bunny a cuddle.
And Prince William couldn’t resist the urge to give his young daughter a cuddle, too!
6. Charlotte speaks her first word in public
After making a beeline for the balloons, Charlotte was overheard shouting, “pop pop!” according to observers. She also called Prince William “dada,” as he and Princess Kate took turns tending to each sibling. “One minute George wanted dad and the next minute George wanted mom,” military mom Kristy Matheson, who brought daughters Lily and Isabelle to the garden party, told PEOPLE. “Will and Kate were doing the juggling act just like the rest of us parents were.”
7. William tries (and fails!) to make balloon animals
George and Charlotte were so taken with the balloon animals that William tried to make one himself. As Will quickly learned, blowing up those balloons is harder than it looks! “We were all sitting around on the carpet and the dads were trying to blow up balloons,” military mom Jeannie Ward recalled.
“William had one balloon he was trying to blow up and my husband was trying too,” Ward continued. “They looked at each other and were like, ‘This is really hard! I don’t know how they do it!’ It was quite funny.”