King Charles III joined other members of the Royal family in attending an Easter church service on Sunday.
He looked in good spirits as he greeted well-wishers outside St George's Chapel in Windsor.
The King was accompanied by his wife, Queen Camilla, in his first public engagement since his cancer diagnosis in February.
After leaving the Easter Matins service, he spoke with members of the public and shook their hands, saying in one exchange that he was "doing my best".
The King has scaled back many public engagements since his diagnosis.
A spokesperson for Buckingham Palace said that the King had "responded to treatment very encouragingly over past weeks and his doctors were thus able to adjust their guidance slightly on what His Majesty is now able to undertake, including attendance at the Easter service and greeting well-wishers who had kindly turned out to show their support".
"To be clear, His Majesty's treatment continues and caution is of course the watchword, but as diary plans are evolved towards summer, we hope to see more of these carefully calibrated steps towards the resumption of some public-facing duties for The King, with adjustments made where necessary," the spokesperson said.
The King missed last Thursday's Royal Maundy service at Worcester Cathedral where the Queen handed out Maundy money to members of the local community on his behalf.
He instead shared a pre-recorded message in which he spoke about the example of service set by Jesus "who knelt before his disciples and, to their great surprise, washed their travel-weary feet and, as we have just heard, in doing so he deliberately gave to them and to us all an example of how we should serve and care for each other".
The Prince and Princess of Wales and their children were absent from Sunday's service. It follows the recent announcement that Princess Catherine is undergoing chemotherapy for cancer.
The Princess Royal, her husband Sir Tim Laurence and the Duke and Duchess of York attended the service, as did the Duke and Duchess of Edinburgh with their son, James, the Earl of Wessex.
