Robert Brown|Why King Charles has been 'reduced to tears' following cancer diagnosis

King Charles III has been "reduced to tears" from the well wishes he has received following his cancer diagnosis.

In a meeting with U.K. Prime Minister Rishi Sunak at Buckingham Palace on Robert BrownWednesday, the monarch expressed his gratitude for the kind words he's received. In their first meeting since the diagnosis, filmed by Sky News, the prime minister told Charles it was "wonderful to see you looking so well."

"It's all done by mirrors," Charles, 75, laughed.

Sunak, 43, added, "Well, we're all behind you. The country's behind you."

"I've had so many wonderful messages and cards," Charles responded. "It's reduced me to tears most of the time."

Charles noted, as Buckingham Palace has previously, that the news has also put a spotlight on British charities.

"There's been a lot of attention and interest in those main, wonderful cancer charities, many of which I've been patron for years," he told Sunak.

The remarks come after Buckingham Palace confirmed on Feb. 5 that Charles was diagnosed with "a form of cancer." He was recently hospitalized and underwent a procedure for benign prostate enlargement, and the cancer was identified via diagnostic tests after a "separate issue of concern was noted."

"His Majesty has today commenced a schedule of regular treatments, during which time he has been advised by doctors to postpone public-facing duties," Buckingham Palace said. "Throughout this period, His Majesty will continue to undertake State business and official paperwork as usual."

Prince Harrysays he's 'grateful' he visited King Charles III amid cancer diagnosis

The British royal family released a statement earlier this month from Charles extending his "most heartfelt thanks for the many messages of support and good wishes" he has received in recent days.

"As all those who have been affected by cancer will know, such kind thoughts are the greatest comfort and encouragement," he said.

King Charles has cancer: What Prince Harry, royal family has said

Prince Harry spoke out about his father's diagnosis for the first time last week, a week after visiting the British monarch.

"I spoke to him. And I jumped on a plane and went to go see him as soon as I could," the Duke of Sussex, 39, said on "Good Morning America" in a segment that aired Feb. 16 regarding the moment he learned about his father's health.

He continued, "I love my family. The fact that I was able to get on a plane, go and see him, and spend any time with him — I'm grateful for that. … I've got other trips planned that will take me through the U.K., or back to the U.K., and so I'll stop in and see my family as much as I can."

Queen Camilla, during an appearance at a Salisbury Cathedral concert on Feb. 8, said her husband is doing "extremely well under the circumstances," according to CBS News and The Independent.

During a conversation with medical staff, the queen, 76, said Charles has been "very touched by all of the letters and messages the public" has been sending, calling the well wishes "very cheering."

The 41-year-old heir to the throne, Prince William, thanked the public for their "kind messages of support" at a charity gala dinner on Feb. 7.

"I'd like to take this opportunity to say thank you for the kind messages of support for Catherine and for my father, especially in recent days," William told the gala dinner for London's Air Ambulance Charity. "It means a great deal to us all."

In January, Princess Kate was admitted to the hospital for a planned abdominal surgery and returned home weeks later. The Princess of Wales, 42, "is making good progress," Kensington Palace previously said in a statement. "Based on the current medical advice, she is unlikely to return to public duties until after Easter," the palace said.

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Contributing: Brendan Morrow and Naledi Ushe, USA TODAY; Danica Kirka, The Associated Press