London — Britain’s Prince William returned to public duty on Wednesday following his wife Kate’s surgery and news that King Charles had cancer, as his younger brother Prince Harry was set to return to the United States after a flying visit to see their father. 

William, the heir to the throne, had postponed all his planned engagements to look after his three children after Kate, 42, underwent planned abdominal surgery on Jan. 16, and spent two weeks in hospital recovering.  

Since then, his father has undergone treatment at the same hospital for an enlarged prostate, before Buckingham Palace announced on Monday that subsequent tests on the 75-year-old monarch had revealed he had a form of cancer. 

On Wednesday, William, 41, made his first official public appearance since the series of health blows to the royals when he carried out an investiture – a ceremony to hand out state honors – at Windsor Castle and will later attend a gala dinner for London’s Air Ambulance Charity. 

With the king postponing public duties as he has out-patient treatment and Kate not expected to return to engagements until after Easter, the onus will be on the remaining royals especially William and Charles’ wife Queen Camilla, to provide the public face of the monarchy. 

Royal author Robert Hardman said William had already taken on substantial state duties towards the end of Queen Elizabeth’s reign when she was hampered by mobility issues. 

“In that regard, it’s not that different but obviously there’s the burden of expectation,” Hardman told Reuters. “On many occasions he will have to stand in, he’ll be sort of quasi head of state in much the same way that Prince Charles was when the queen was infirm.” 

On Tuesday, the king travelled with Camilla to Sandringham House, his home in eastern England, after a brief meeting of about 30 minutes with his estranged son Prince Harry who had just flown in to see his father after the king told him he had cancer. 

Harry has barely been on speaking terms with many of the Windsors following his criticism of the monarchy since stepping down from royal duties almost four years ago.  

A royal source said there were no plans for him to see his elder brother William during his visit to Britain. After only about 24 hours in Britain, Harry was seen at Heathrow Airport from where he was expected to fly home to California where he now lives with wife Meghan and their two children. 

Despite the diagnosis, Charles is planning to continue with much of his private work as monarch and dealing with state papers. He will hold his regular weekly audience with Prime Minister Rishi Sunak by phone on Wednesday, Sunak’s spokesman confirmed.  

Buckingham Palace has not given any details of the condition other than to say it was not prostate cancer, but said the king was remaining “wholly positive” and looking forward to returning to public duty as soon as possible.