Scotland's first minister and other political leaders have sent messages of support to King Charles after the announcement that he has cancer.
Humza Yousaf said his "thoughts and prayers" were with the King and he wished him a speedy recovery.
The Scottish Conservative and Scottish Labour leaders also sent their best wishes to the Royal Family.
Buckingham Palace has said the cancer was discovered during recent treatment for an enlarged prostate.
The type of cancer has not been revealed but it is not prostate cancer, and the King has already begun medical treatment.
Mr Yousaf said: "Can I send my thoughts and my prayers to His Majesty the King and wish him well for a full recovery and a return to public life.
"May I also send my best wishes and my thoughts with Her Majesty the Queen and all the members of the Royal Family who will be deeply worried at this time.
"I don't think it matters if you are a member of the Royal Family or not, if a family member has cancer that is always going to be extremely worrying indeed so I want to send them my very best wishes, not just on behalf of myself personally but from the government I lead and on behalf of the entire nation."
The King has postponed public duties while he undergoes regular treatment, the palace statement said.
King Charles was in Scotland a few weeks ago with Queen Camilla on a private visit to Birkhall on the Balmoral Estate in Aberdeenshire.
They travelled up after spending Christmas on the Sandringham Estate with other members of the Royal Family.
Buckingham Palace confirmed in a statement on 17 January that the King had sought treatment for an enlarged prostate and would attend hospital for a corrective procedure.
The following day, during a visit to Aberdeen Art Gallery, the Queen said he was "fine" and was looking forward to getting back to work. The King left Scotland a day later as he headed to Sandringham to rest before the procedure.
Mr Yousaf spoke of the King's role in championing good causes and highlighting climate change, and said he would be missed during his treatment.
Scottish Conservative leader Douglas Ross said: "I join people across the UK and around the world in sending my best wishes to His Majesty for a full and speedy recovery. "My thoughts are with the King and the entire Royal Family as he begins his treatment."
Scottish Labour leader Anas Sarwar said: "My best wishes are with His Majesty and all the Royal Family at this time. I join the nation in wishing His Majesty a full and speedy recovery."