Prince William congratulates his wife Kate on her birthday

The Prince of Wales wished his wife, Catherine, a happy birthday as she turns 43.

"To the most amazing wife and mother. The strength she has shown over the last year is remarkable. George, Charlotte, Louis and I are so proud of you. Happy birthday, Catherine. We love you," William wrote on social media.

The princess returned to her royal duties after undergoing preventative chemotherapy treatment as a result of being diagnosed with cancer last year, the BBC reported.

Kensington Palace released the personally written message from William along with a never-before-seen photo of Catherine taken by photographer Matt Porteous at Windsor last summer.

In the black and white photo, the princess looks relaxed and smiling, wearing a white shirt, jeans and a scarf.

The royal family also wished her a happy birthday.

The monarchy's official media account shared a message on X saying, "Happy Birthday Princess of Wales!" along with a birthday emoji.

The post also featured a photo of Catherine collecting flowers from well-wishers while attending church in Sandringham on Christmas Day.

It was the last time the Prince and Princess of Wales were seen together in public.

Catherine is understood to be celebrating her birthday at her home in Windsor, along with William and their three children - Prince George, Princess Charlotte and Prince Louis. | BGNES