King Charles III said he had been reduced to tears by the messages he has received from people since his cancer diagnosis, as he held his weekly audience with the prime minister for the first time since stepping away from public duties to focus on his treatment.

Charles also met Wednesday with the Privy Council – a group of senior officials who meet about once a month to advise the king on government matters. While the 75-year-old head of state remains absent from public engagements, he has said he intends to continue to perform his state duties.

Wearing a navy blue suit and tie, Charles joked with Prime Minister Rishi Sunak before their formal meeting at Buckingham Palace.

“Wonderful to see you looking so well,” Sunak said cheerfully in video released by the palace.

“It’s all done by mirrors,” Charles laughed.

“We’re all behind you,” Sunak said. “The country is behind you.”

“I’ve had so many wonderful messages and cards,” Charles responded. “It’s reduced me to tears most of time.”

It was the first time Charles has been filmed carrying out official duties since late last year. The monarch normally curtails his public schedule for several weeks around the Christmas and New Year holidays, which was followed by the announcement of the king's diagnosis earlier this month.

Buckingham Palace announced that the king would be treated for cancer less than three weeks after he was treated for an enlarged prostate. While palace officials didn’t disclose the type of cancer, they said it wasn’t prostate cancer.

Charles said he was also gratified to see how the announcement of his diagnosis had boosted support for cancer charities in the United Kingdom.