Prince William turns 6-21 today at the age of 42, and his family is celebrating him like their sweet tradition: in exclusive photos posted on social media.

In the new photo, taken by his wife Princess Kate, of course, the Prince of Wales jumps into the air on a lawn bank while holding hands with children Princess Charlotte, 9, Prince Louis, 6, and Prince George, 10. They seem to be somewhere away for their summer vacation because all the sand is visible and there is a beautiful blue sky.

The caption was written from the point of view of the child, but was signed by Kate: "Happy Birthday Dad, we all love you so much!" Cx"

Obviously, the photo was an instant fan favorite, one Royal watcher wrote, "Probably the best photo they've ever shared- so relaxed, normal, and full of joy."

Just a few days ago, 3 Welsh children came to sign off on their first social media post while celebrating their father on Father's Day. They wrote in that post, "We love you, Dad. Happy Father's Day ♥G, C&L"

Father's Day photos seem to have been taken in the same place, the beach, on another day, but this time you can see the sea. [Instagram]

Meanwhile, King Charles also celebrated his eldest son on social media and shared an incredible black and white photo of him in his instagrammed story of holding William as a baby instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrammed instagrams. He wrote, "Wish the Prince of Wales a very happy birthday!""

Kate has shared a handful of other family photos over the past few months, showing that she has been actively involved in the lives of her children while she is undergoing cancer treatment.

In a recent statement announcing her upcoming appearance on Trooping The Colour, Kate said: "I'm making good progress, but as anyone who's been through chemotherapy knows, there are good days and bad days. On those bad days you feel weak and tired, and you have to bow to your body resting. But on a good day, when you feel strong, you want to make the most of your mood.

The Princess shared her cancer diagnosis publicly for the first time in late May.