Prince William is honoring "incredible wife and mother" Kate Middleton on her birthday.
"The strength you've shown over the last year has been remarkable," he wrote, in an apparent reference to her recent battle with cancer.
Although she did not share specific details about her illness, Middleton announced she finished chemotherapy in September.
"The last nine months have been incredibly tough for us as a family," she said at the time. "Life as you know it can change in an instant and we have had to find a way to navigate the stormy waters and road unknown."
In his birthday post, William shared a black-and-white photo of Middleton, seen wearing denim, with a blazer and scarf over a white blouse.Middleton tucks her hands into her pockets and smiles as she looks away from the camera.
"George, Charlotte, Louis and I are so proud of you," William wrote, referring to the couple's three children. "Happy Birthday, Catherine. We love you."
