Prince William Promises to 'Look After' Kate Middleton amid Cancer Treatment While Receiving Cards for Her and King Charles

On April 18, the Prince of Wales, 41, made his first public engagement since his wife shared the news of her cancer diagnosis with the world. He appeared moved when a volunteer at food distribution charity Surplus to Supper in Sunbury-on-Thames surprised him with cards for his wife, Princess Kate, and his father, the King, who both postponed public-facing duties while receiving cancer treatment.

"Oh, some cards, you're very kind. Thank you very much," Prince William told volunteer Rachel Candappa in a video shared to X by Lizzie Robinson of ITV.

When Candappa, 71, told the royal to look after his wife, he placed a hand on her shoulder and said, "I will," The Telegraph reported.

According to Chris Ship of ITV, the volunteer "told us she spent ages last night thinking of what to write in her message inside."

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The Prince of Wales' second stop of the day was to the Hanworth Centre Hub, a youth center that provides a range of services to create a safer and better-connected community and receives a regular delivery from Surplus to Supper. There, he received a bouquet and more well wishes for Princess Kate.

Siobhan Donoghue, CEO of Perfectly Imperfect CIC, one of the groups who receive provisions from Surplus to Supper, tells PEOPLE, "We had a flower arrangement from the staff and one from the young people and volunteers. He was very thankful that we were asking after her."

However, Prince William kept his attention on the work they were doing to reduce food waste.

"You could see he very much wanted to focus on us and genuinely learn how we impact the community we serve," Donoghue says. "He said to the young people that they had really helped give him that picture of what we do and how important it is to the community."

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Buckingham Palace announced the 75-year-old King's diagnosis on Feb. 5 in a statement following his treatment for a benign enlarged prostate in January, though a spokesman confirmed it is not prostate cancer.

A few weeks later, on March 22, the Princess of Wales, 42, announced in a video message that she was undergoing chemotherapy after post-operative tests following her abdominal surgery in January "found cancer had been present."

Prince William's outings linked to tackling food waste marked his return to royal duty after a few weeks off with his family following Princess Kate's announcement and during a school break for their children, Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5. The royal mom may have strategically waited to make the announcement about her health until her kids were out of the classroom to create space for their family to have private time together.

The Prince of Wales similarly cleared his calendar following his wife's abdominal surgery on Jan. 16 to be by her side and keep their kids' schedule as normal as possible.

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The heir to the throne previously expressed thanks for the kind messages sent to his family following the palace announcement about the King's cancer diagnosis.

While speaking on stage at London's Air Ambulance Charity Gala Dinner on Feb. 7, Prince William said, "I'd like to take this opportunity to say thank you, also, for the kind messages of support for Catherine and for my father, especially in recent days. It means a great deal to us all."

"It's fair to say the past few weeks have had a rather 'medical' focus. So I thought I'd come to an air ambulance function to get away from it all!" he quipped.

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King Charles has continued to work behind the scenes while receiving cancer treatment, hosting small audiences and even surprising with a mini walkabout following church at St. George's Chapel at Windsor Castle on Easter Sunday. 

"Get well soon, Your Majesty," one well-wisher said in video shared to X by Rebecca English of the Daily Mail, prompting King Charles to reply, "I'm doing my best!"

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Princess Kate has kept a low profile since sharing the news about her health on March 22, referencing the intention in the self-written address.

"We hope that you will understand that, as a family, we now need some time, space and privacy while I complete my treatment. 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," she said in the speech, filmed in the garden of Windsor Castle.

The Princess of Wales "will return to official duties when she is cleared to do so by her medical team. She is in good spirits and is focused on making a full recovery," a Kensington Palace spokesperson said at the time of her cancer news announcement.

A palace source later told PEOPLE that Princess Kate might join family events when she feels able, though it may not signal a full return to work.