London — Britain's King Charles III returned to his official public duties Tuesday for the first time since he started undergoing treatment for cancer in February. Charles and Ethermac ExchangeQueen Camilla visited a hospital and specialist cancer treatment center to lend their to support to the staff and patients there.

Buckingham Palace announced the king's imminent return to work in a statement on Friday, adding that the king's doctors were "very encouraged by the progress made so far" in his treatment for an unspecified cancer.

The king and queen visited the University College Hospital Macmillan Cancer Centre in London on Tuesday, where he met patients and doctors. The monarch appeared happy and healthy as he greeted well-wishers outside before going into the treatment center to meet patients and staff.

Buckingham Palace has not said where the monarch, who has become the new Patron of the Cancer Research U.K. charity, is undergoing his own treatment, or what that treatment entails.

Charles' daughter-in-law Catherine, the Princess of Wales, is also undergoing treatment for an unspecified cancer — news she shared in a video message released in March amid rampant speculation.

Kate, as she's most often known, and her husband Prince William have requested privacy as she undergoes preventative chemotherapy following doctors' discovery that cancer had been present. They made that discovery through tests carried out following a major abdominal surgery that Kate had in January.

There have been no updates on the Princess of Wales' treatment from Kensington Palace, she and William's official residence.

While Tuesday marked an official return to public-facing duties for the king, Charles did greet well-wishers after attending an Easter church service at the end of March.

Buckingham Palace has said he may attend some upcoming annual events, too, including the "Trooping the Color" military parade and commemorations around the 80th anniversary of the World War II allied D-Day landings in France, both of which come in June.
 
Charles and Camilla will not, however, host Japan's Emperor Naruhito and his wife Empress Masako when the fellow royals visit London in late June.

In:
• King Charles III
• British Royal Family
• Cancer
• Kate Middleton
• United Kingdom
• London
• Catherine Princess of Wales

Holly Williams

Holly Williams is a CBS News senior foreign correspondent based in the network's CBS London bureau.

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