It's thought the photo was taken in Jordan, the same place as their 2021 Christmas card photo, as the tots pulled faces against the sandy, rocky backdrop.
The photograph bears a strong resemblance to Prince Louis' cheeky personality shown at the Queen's recent Platinum Jubilee celebrations, as he sits on William's shoulders.
"Wishing a Happy Father’s Day to fathers and grandfathers across the world today!" the royals posted on Instagram alongside the snap.
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