The 41-year-old was formally invested as chief scout on Thursday at Scout Park in north-east London where he spent time in Cub Scouts as a child. Chief scouts are appointed for a five-year tenure but may serve for a longer period. Mr Fields will be the 11th person to hold the title.

Since revealing her health challenges, Kate has been largely absent from public life. She was last seen several weeks ago with husband William, their children and the rest of the Royal Family as they headed to Crathie Kirk near Balmoral during their annual summer holiday.

She also attended the mens final at Wimbledon in July, where she presented the trophy to Carlos Alcaraz and made her triumphant return after her diagnosis at Trooping the Colour in June. In a statement before that, she candidly spoke about her recovery.

She explained: “I am making good progress, but as anyone going through chemotherapy will know, there are good days and bad days,” the princess said. “On those bad days you feel weak, tired and you have to give in to your body resting. But on the good days, when you feel stronger, you want to make the most of feeling well.

“My treatment is ongoing and will be for a few more months. On the days I feel well enough, it is a joy to engage with school life, spend personal time on the things that give me energy and positivity, as well as starting to do a little work from home.” Kate’s message today comes just a day after her husband William returned to work following the summer break and with Prince George, Princess Charlotte and Prince Louis back at school.

Yesterday, he thanked artists for taking part in a groundbreaking homelessness exhibition as he sported his summer beard in public for the first time. William debuted his new look in an online video with Kate in August, when they praised the achievements of the nation’s athletes after the Paris Olympics.

The stubble was still in place as he toured Homelessness: Reframed, an exhibition at London Saatchi Gallery, which aims to give a fresh perspective on the issue, with sculptures, photographs and everyday objects given a new life by artists who may have slept rough.