A new photo of William, the Prince of Wales, and his three children was released Friday by Kensington Palace to celebrate the future British monarch‘s 42nd birthday.

The image, published on the joint social media channels of Prince William and his wife Catherine, the Princess of Wales, included the message: “Happy birthday Papa, we all love you so much!” It was signed “Cx,” an abbreviation for the Princess of Wales, who’s often referred to as Princess Kate.

The palace said the image was taken by Kate in Norfolk, southeast England, in May. Kate has been undergoing treatment for an unspecified form of cancer. She made her first public appearance last weekend, at a parade to mark King Charles III’s birthday, since announcing her diagnosis in late March.

The image shows Prince William, Prince George, Princess Charlotte and Prince Louis jumping off a sand dune.

The Royal Family social media account, where Buckingham Palace posts on behalf of William’s father King Charles III and Queen Camilla, also featured a birthday message for the Prince of Wales, with a photo showing Charles holding William when he was a baby.

King Charles is also undergoing cancer treatment. The family has not revealed what type of cancer he or Kate were diagnosed with.

In March, Kate issued an apology for causing confusion with a photo she posted showing her with her children that had been altered. She admitted to editing the photo, which was posted to mark Mother’s Day in the U.K. The blatantly altered image sent rumors swirling about her health, as it was released before she went public with her cancer diagnosis, but after weeks of her remaining out of public view.