The British Prime Minister said he is thankful the King’s cancer has been “caught early” as he wished him a full recovery.
Charles, 75, is facing regular treatment for cancer after his shock diagnosis was uncovered during his recent hospital stay for a procedure on an enlarged prostate.
The King, who has postponed all his public duties, returned to London from Sandringham yesterday and has already begun his medical care as an outpatient under the supervision of his specialist team of doctors.
Mr Sunak said he was left “shocked and sad” when he was told about the King’s cancer diagnosis.
He told BBC Radio 5 Live: “All our thoughts are with him and his family.
“Thankfully, this has been caught early.”
He said that everyone will be hoping the King “gets the treatment that he needs and makes a full recovery”.
“That’s what we’re all hoping and praying for, and I’m of course in regular contact with him and will continue to communicate with him as normal.”
Buckingham Palace confirmed the King, who only acceded to the throne 17 months ago, does not have prostate cancer.
Further details of his condition have not been disclosed, and the Palace, which announced the news in a statement at 6pm yesterday, asked for privacy and only confirmed it is a “form of cancer”.
Charles was diagnosed after a “separate issue of concern was noted” and investigated while he was being treated for his benign prostate condition.
He has started a schedule of regular treatments but has been advised to postpone his public-facing duties.
He will carry on working behind the scenes on state business and official papers.
President Higgins sends best wishes
In a statement yesterday, President of Ireland Michael D Higgins said he “is very sorry and concerned” to hear of King Charles’ medical diagnosis.
President said he sent his best wishes on behalf of the people of Ireland to Charles and his family for his treatment and full recovery.
Northern Ireland’s First Minister Michelle O’Neill wished Charles a full and speedy recovery.
“I am very sorry to hear of King Charles’ illness and I want to wish him well for his treatment, and a full and speedy recovery,” she said.