Kate Middleton is celebrating her 43rd birthday and "looking after herself" after completing chemotherapy treatment, a family friend tells PEOPLE.

Princess Kate has been wished a very happy birthday by King Charles and Queen Camilla. Taking to social media, the couple's official social media account wrote "Happy Birthday to The Princess of Wales!" alongside a cake emoji. A picture of the princess from the recent Christmas walkabout was shared alongside the message.

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,

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.

Happy Birthday, Princess Kate! Express.co.uk shares pictures of 11 of the royal's iconic moments over the years.

Prince William celebrated wife Kate Middleton’s 43rd birthday with a touching tribute heralding her ‘strength’ over ‘the last year’ as she battled cancer

The Prince of Wales shared a new picture and described his wife as 'remarkable' in a touching birthday tribute on Instagram.

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

Kate Middleton is 43! The Princess of Wales is celebrating her birthday surrounded by those nearest and dearest to her on Thursday, The Post can reveal. While Princess Catherine has spent much of her time at Sandringham Estate in Norfolk,

Prince William is celebrating his love and admiration for Kate Middleton as she marks her 43rd birthday. In a message posted to the couple's social media, William, 42, paid tribute to Kate after a year in which she had a major operation,