The Prince and Princess of Wales have marked their 13th wedding anniversary by releasing a previously unseen photo from their personal collection.

Taking a moment amid the princess’s cancer battle, the royal couple shared the image to their social media forums on Monday (UK time).

“13 years ago today!” the post said, alongside a black-and-white portrait by photographer Millie Pilkington.

The intimate image caught the attention of royal watchers because it appeared to come from the couple’s own personal collection, rather than being taken by a news service.

The bonus photo will thrill royal fans, who have been starved of images of Kate since she withdrew from public life in January to undergo surgery.

Last week, the Prince and Princess of Wales released the much-anticipated birthday shot of their youngest son, Prince Louis, for his sixth birthday.

In the latest image, a beaming Kate holds a bouquet of lily of the valley, the late queen’s favourite flower, as she stands with her groom.

Kate wears her white lace-covered gown by Sarah Burton for Alexander McQueen and Queen Elizabeth’s Cartier halo tiara.

Prince William wears the uniform of the Blues and Royals, which he changed into after the wedding ceremony.

Tweet from @KensingtonRoyal

Kate has been out of the public eye since the royal family’s traditional Christmas Day church service at Sandringham.

First she had major abdominal surgery in January, and then – in a video that sent shockwaves around the world – revealed she was being treated for an unspecified cancer.

The 42-year-old princess’s absence sparked weeks of frenzied speculation online about her health.

It culminated in paparazzi photos showing her in a car with her mother, Carole Middleton, and a viral video of her with William at a farm shop in Windsor.

“We hope that you will understand that, as a family, we now need some time, space and privacy while I complete my treatment,” Kate said in her video in mid-March.

“My work has always brought me a deep sense of joy and I look forward to being back when I am able, but for now I must focus on making a full recovery.”

After the video, the Wales family disappeared from public view – reportedly taking shelter at their country estate, Anmer Hall – for the Easter break.

Last week, with the three children back at school, Prince William resumed limited public duties with an outing to a food charity.

There is still no date for Kate’s return.

However, high on the agenda of royal fans will be the expectation of a photo for Princess Charlotte’s ninth birthday on Thursday.

Elsewhere, the King returns to public duties after his own cancer treatment later this week. He and the Queen will make a symbolic visit to a cancer centre.