In his first statement since being diagnosed with cancer, Britain's King Charles III on Saturday thanked well-wishers in a note posted on the monarch's website and the royal family's official page on social media platform X, formerly known as Twitter.

"I would like to express my most heartfelt thanks for the many messages of support and good wishes I have received in recent days," Charles said in a statement.

Buckingham Palace announced on Monday that 75-year-old Charles has been diagnosed with a form of cancer and that he would be postponing some engagements to undergo treatment.

The diagnosis comes just 17 months into Charles' reign, following the death of his 96-year-old mother, Queen Elizabeth II, in September 2022.

The king also said it was heartening to hear how his diagnosis had helped to shine a light on the organizations that support cancer patients in the United Kingdom and elsewhere.

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

News of his cancer came after Charles spent three nights in the hospital last month when he underwent a corrective procedure for a benign enlarged prostate.

Buckingham Palace has not given any details of his condition other than to say it was not prostate cancer but said the king was remaining "wholly positive" and looking forward to returning to public duty as soon as possible.