The Prince of Wales posted a birthday message for his wife, Catherine, Princess of Wales to social media on Thursday to celebrate her 43rd birthday.

Prince William pays tribute to ‘incredible wife’ Kate Middleton as princess turns 43 - Princess celebrating 43rd birthday at home after a challenging past 12 months

King Charles and Queen Camilla are wishing Kate Middleton a happy birthday! See the royal couple's tribute as the Princess of Wales turns 43.

Catherine, Princess of Wales, turned 43 on Thursday, with her husband Prince William praising her "strength" fighting cancer during the past year.

The Princess of Wales was most recently seen on Christmas Day, where she stepped out in sync with Prince William and their kids Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6, for church at St. Mary Magdalene on the Sandringham estate.

Prince William has sparked a fan frenzy with his birthday message to his "incredible" wife, the Princess of Wales. The royal is celebrating her 43rd birthday today, with the family understood to be celebrating quietly at their home in Windsor.

The Princess of Wales is celebrating at home in Windsor with the Prince of Wales, with Prince George, Princess Charlotte and Prince Louis spending the day at school before a family celebration in the evening.

Kate Middleton, who is celebrating her 43rd birthday on Jan. 9, has proven herself to be the shiniest jewel of the British monarchy. The princess is married to Prince William, heir to the throne.

Kate Middleton is celebrating a big milestone this week, and after the year she's had, her husband Prince William is planning on making her birthday celebration extra special this year. Middleton is turning 43 on Thursday,

The royal family has wished the Princess of Wales a happy 43rd birthday. Future queen Kate is celebrating at home in Windsor, with the Prince of Wales and Prince George, Princess Charlotte, and Prince Louis.