The monarch, 75, smiled and waved at a crowd of more than 100 well-wishers as he visited the Sandringham Estate Chapel alongside his wife Queen Camilla, 76, before being greeted by rev Canon Paul Williams, according to MailOnline .
Wearing his signature long brown coat and using an umbrella as a walking stick, the King strolled at his usual brisk pace for the 11am service at the Norfolk estate.
Crowds, who gathered to show the couple support following Charles’ diagnosis watched on from behind locked gates, said he ‘seemed like he was doing really well’.
Last night the King offered his ‘heartfelt thanks’ to the British public for their ‘many messages of support and good wishes’ almost a week after it emerged he was being treated for a ‘form of cancer’.
In a letter published by Sandringham House, where he has been staying since leaving the London Clinic on January 29, the King said he was ‘heartened’ to hear his experience is inspiring others up and down the country to get themselves checked.
The note, signed by Charles R, read: ‘I would like to express my most heartfelt thanks for the many messages of support and good wishes I have received in recent days.
‘As all those who have been affected by cancer will know, such kind thoughts are the greatest comfort and encouragement.
‘It is equally heartening to hear how sharing my own diagnosis has helped promote public understanding and shine a light on the work of all those organisations which support cancer patients and their families across the UK and wider world.
My lifelong admiration for their tireless care and dedication is all the greater as a result of my own personal experience.’
The King was seen in public for the first time since his cancer diagnosis on Tuesday as he left Clarence House the day after starting his treatment, following a brief reunion with the Duke of Sussex.
Buckingham Palace confirmed the King, who only acceded to the throne 17 months ago, does not have prostate cancer, saying only that he has a ‘form of cancer’.
He was diagnosed after a ‘separate issue of concern was noted’ and was investigated while he was being treated for his benign enlarged prostate.