While there's no denying the three Cambridge kids are total cuties, with just under five years between Prince George and Prince Louis it's not always easy to see the close resemblance between the brothers.
But thanks to one superfan, we've just had our first look at the royal youngsters side-by-side at the same age - and the similarities are uncanny!
The picture - which was posted on the Instagram account @loveprincessdiana - shows Louis when he was just a few months old and Prince George at a year old, and they have near-identical expressions and features.
But apparently it's not just their physical resemblance which bonds the Cambridge brothers together, they're also said to be very close.
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According to a royal source: "They are close in age, and they spend so much time together."
"Playdates [with outsiders] can be tricky, so they learn to lean on each other."