Prince George Is Prince William's Twin — After Kate Said Louis Is the Only One Who Looks Like Her!

Prince George is soaking up the sun in his 9th birthday portrait. But it's not just his adorable grin that has royal fans talking — the young royal is the spitting image of his dad Prince William.

From his blonde locks and side part to his twinkling eyes and infectious smile, George closely resembles his father at the same age in the photo, which mom Kate Middleton took while the family was on holiday in the U.K. earlier this month.

George isn't the only Cambridge sibling who twins with William. His 7-year-old sister Princess Charlotte also bears a striking resemblance to the Duke of Cambridge.

Even William and Kate Middleton are aware of Charlotte's mini-me status. The couple confused a picture of William as a child with Charlotte during an outing in 2020.

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The Duke and Duchess of Cambridge/twitter; Anwar Hussein/Getty Prince George at 9 years old and Prince William at 9 years old

"Is that me?" Prince William said while pointing to a portrait of himself as a youngster, before commenting that it looked like his daughter. "Because that looks just like Charlotte. That is incredible."

Kate was in agreement: "It looks so much like Charlotte."

The Duchess of Cambridge via Getty images; Daily Mirror/Mirrorpix/Getty Images Princess Charlotte and Prince William

The Duchess of Cambridge has her own twin in son Prince Louis, who celebrated his fourth birthday on April 23. The royal mom of three has even acknowledged that her youngest child is taking after her looks.

"Everyone always comments on how Louis is the spitting image of Kate," a friend previously told PEOPLE. "She loves it and thinks it's very sweet — she often jokes that he's the only one of her kids who actually looks like her!"

The Duchess of Cambridge; SplashNews.com Prince Louis and Kate Middleton

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Kate and William are navigating a path that allows their three children to grow up as normally as possible while also preparing them for their roles within the royal family — roles they may already know about.

Samir Hussein/WireImage Prince George, Prince Louis and Princess Charlotte

"George is more reserved, and Charlotte is more outgoing," an insider told PEOPLE. "Maybe it's because he's the heir and one day he might be King."

And Louis showed off his "cheeky" side during Queen Elizabeth's Platinum Jubilee celebrations last month.

"He's a cheeky monkey — a typical third child," someone who knows the family recently told PEOPLE. "It's nice that the world got to see him enjoying himself."