Prince William has praised his wife Kate Middleton in a touching birthday tribute.

In March of last year, the Princess of Wales announced she was undergoing treatment for cancer, with her diagnosis sending shock waves through the royal family.

However in September, she returned to social media to reveal she had finished chemotherapy.

Prince William has praised his wife Kate Middleton in a touching birthday tribute. Pic: Samir Hussein/WireImage

On her 43rd birthday, her dotting husband has shared some touching words, praising her strength in the last year.

The Prince of Wales wrote: ‘To the most incredible wife and mother. The strength you’ve shown over the last year has been remarkable.

‘George, Charlotte, Louis and I are so proud of you. Happy Birthday, Catherine. We love you. W’

The Princess of Wales returned to work in September after completing chemotherapy for her undisclosed form of cancer.

The 42-year-old attended a meeting with her Early Years task force at Windsor Castle, marking her third appearance of the year and her first work engagement.

A statement regarding Kate’s return to work read; ‘The Princess of Wales, Joint Patron, the Royal Foundation of The Prince and Princess of Wales, this afternoon held an Early Years Meeting at Windsor Castle.’

In March of last year, the Princess of Wales announced she was undergoing treatment for cancer, with her diagnosis sending shock waves through the royal family. Pic: Danny Lawson/PA Wire

Reports suggest the meeting concerned the Shaping Us campaign, which aims to raise the profile of the importance of early childhood development.

Announcing her diagnosis in March, Kate confirmed that she had undergone major abdominal surgery in January, with her condition at the time thought to be non-cancerous.

Though the surgery was successful cancer was found following further tests.

‘My medical team therefore advised that I should undergo a course of preventative chemotherapy and I’m now in the early stages of that treatment.’

Kate Middleton

Sharing that the diagnosis was a ‘huge shock’ for the family, the Princess said that they have been ‘doing everything we can to process and manage this privately for the sake of our young family.’

Kate went on to request ‘some time, space and privacy while I complete my treatment’ and expressed her excitement at returning to duties ‘when I am able.’