Prince William and Princess Kate have added a sweet new picture as the cover of their Instagram Stories Highlight for August.

It is a previously unseen picture of the Prince and Princess of Wales that looks like an outtake from their Paris Olympics video - which was uploaded two months ago.

A zoom into the image shows Kate and William, both 42, wearing similar blue polo shirts and standing outdoors.

In the video issued on the day of the closing ceremonies for the global games in August, Kate wore a striped Breton top, whilst William sported a cornflower blue Adidas polo with a Team GB logo over Olympics rings.

On closer inspection of the highlights cover picture, it looks like Kate was wearing a navy version of the same shirt that her husband had on.

In the video posted on August 11, Kate can be heard saying: "From all of us watching at home, congratulations to Team GB."

William can be heard saying: "Well done on all you've achieved, you've been an inspiration to us all."

In a surprise to fans, the Prince of Wales debuted a new beard - a new look he now seems to be sticking to having made several appearances since.

The video also bore significance as it marked Kate's third appearance amid her cancer treatment.

Last month, Kate then revealed that she had completed chemotherapy. The royal appeared in an emotional video of her and Prince William with their kids Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6.

Speaking about her health, she said: "Doing what I can to stay cancer-free is now my focus.

"Although I have finished chemotherapy, my path to healing and full recovery is long and I must continue to take each day as it comes.

"I am, however, looking forward to being back at work and undertaking a few more public engagements in the coming months when I can."