Britain's King Charles greeted well-wishers after attending Easter services in Windsor on Sunday, in his first appearance at a public event since Buckingham Palace revealed his cancer diagnosis in February.

The 75-year-old monarch shook hands and chatted with people in the crowd outside after attending an Easter service at Windsor Castle, the Associated Press reported.

Charles made his way down a rope line outside St. George's Chapel on a chilly morning.

"You're very brave to stand out here in the cold," Charles told onlookers.

The king seemed to enjoy the interaction and it was a positive sign that he felt able to shake hands, according to the BBC.

His son, Prince William, and his family did not attend the service. William's wife Kate announced in a video earlier this month that she was undergoing chemotherapy after her own cancer diagnosis.

Charles has been performing official duties since his diagnosis, such as regular meetings with the prime minister, but has avoided public events, according to Reuters.

The king has been undergoing treatment for an unspecified type of cancer and has been limiting public interaction to avoid getting an infection.

The British media has reported that Charles is expected to slowly increase his public appearances in the weeks ahead.

"Keep going strong," one member of the crowd shouted as Charles and Queen Camilla passed them.