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.

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.

Princess Kate is celebrating her 43rd birthday. Her husband, Prince William, honored the "most incredible wife and mother" in a new post.

Prince William praised the strength of the Princess of Wales after a turbulent year, offering a 43rd birthday wish on social media that described her as an incredible wife and mother

In the photo, Middleton traded sleek coats and heels for something more casual. She wore a dark blazer jacket rolled and cuffed at the sleeves with a crisp white button-up top. Completing the outfit was a checked plaid printed scarf worn around the neck and fitted dark jeans with light whiskering at the hips.