Kate Middleton is officially 43 years old! The Princess of Wales marked her latest birthday on Jan. 9, releasing a stunning portrait of herself beaming on social media. The photo was accompanied by a touching message from her husband,

After a challenging year, Prince William has shared a moving tribute to his wife, Kate Middleton, on her 43rd birthday describing her as “the most incredible wife and mother,” alongside a new portrait.

Kate, the Princess of Wales, turns 43 on Thursday, capping what was a tumultuous year for the mother of three and wife of Prince William. Kate, who was born Jan. 9, 1982, is expected to spend her birthday privately with William and their kids -- Princes George and Louis and Princess Charlotte -- at home in Windsor, England.