Princess Kate is celebrating 43 years around the sun.
The British royal is coming off of a “challenging” year following her cancer diagnosis and treatment. But her husband, Prince William, highlighted Kate’s “strength” in a birthday post on Instagram Thursday.
“To the most incredible wife and mother. The strength you’ve shown over the last year has been remarkable,” William captioned a black and white photo of Kate on their joint account. “George, Charlotte, Louis and I are so proud of you. Happy Birthday, Catherine. We love you.”
The photo shows Kate in a light button-up, dark jeans, a shepherd check scarf and a dark jacket.
At a Christmas concert in the U.K. last month, Kate made a rare comment about her trying year. “I didn’t know this year was going to be the year that I’ve just had,” the princess told Paloma Faith, one of the stars set to perform at the concert, in a video posted to X by Channel 5 news.

Public discourse about her whereabouts after taking a step back forced the royal to publicly announce her cancer diagnosis. Kate revealed in March that she would undergo a course of preventative chemotherapy after having abdominal surgery. And while her treatment ended in September, the princess shared in a video posted to social media at the time: “My path to healing and full recovery is long and I must continue to take each day as it comes.”
Kate has increasingly made public appearances as she recovers from treatment, including at the Trooping the Colour parade, Wimbledon, church services including a Christmas Day church service at St Mary Magdalene Church in eastern England, and her annual Christmas carol service. At the latter event with her family, Kate spoke about unity, reflecting on “our own vulnerabilities” during the holiday season and the need for empathy.
She said, “It is when we stop and take ourselves away from the pressures of daily life, that we find the space to live our lives with an open heart, with love, kindness and forgiveness, so much of what the Christmas spirit is all about.
“The Christmas story encourages us to consider the experiences and feelings of others. It also reflects our own vulnerabilities and reminds us of the importance of giving and receiving empathy, as well as just how much we need each other in spite of our differences. Above all else, it encourages us to turn to love, not fear.”