Prince William kept his positive COVID-19 diagnosis in April a secret to reportedly not worry people. Around that time, his father, Prince Charles, was also in self-quarantine.

The Duke of Cambridge was treated by palace doctors and acted in accordance with government guidelines by isolating at his family home, Anmer Hall, in Norfolk.

The second-in-line to the throne was diagnosed shortly after his father, the heir to the throne, declared he had contracted the novel coronavirus in late March.

He kept the diagnosis furtive because "he didn't want to alarm the nation."

The duke kept his telephone and video engagements, totaling 14, without divulging his diagnosis.

Kensington Palace declined to comment on the revelation on Sunday but made no denial of the report.

Prince William shared that he contracted the coronavirus when he talked to someone at a public engagement. According to a source, "William was hit pretty hard by the virus ... it really knocked him for six. At one stage he was struggling to breathe, so obviously everyone around him was pretty panicked," reported People.

His decision to keep the diagnosis in secrecy has prompted questions from many. A royal commentator claimed the "controversial" action displayed how he intently guards his privacy.

In March, Prince Charles had mild COVID-19 symptoms, and in his first public engagement upon recovery, he disclosed he lost his sense of smell and taste while he had the virus.

Prince William had a public engagement in mid-October with his grandmother Queen Elizabeth II. The Queen was making her first public engagement beyond the borders of a royal residence since March.

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According to the prince, who told an observer at an engagement, "There were important things going on, and I didn't want to worry anyone," reported BusinessWorld.

BBC confirmed the news from sources on Sunday. The office of Prince William declined to give a comment to the news outlet officially.

The 38-year-old's apparent diagnosis was revealed as the United Kingdom works up another national lockdown from Thursday.

On April 17, Prince William and his wife, Kate Middleton, spoke to BBC Breakfast. They shared gratitude for frontline workers, and the prince said he was concerned for his 71-year-old father, who tested positive for COVID-19.

After the U.K. Prime Minister Boris Johnson was hospitalized, Queen Elizabeth II then delivered her "We will meet again" address. Prince William felt it was not yet the right timing to say anything.

According to a source, "He felt there were more important things going on in the country. But as a result of his own experiences, he realises absolutely anyone can catch this awful disease - and knows how imperative it is that we all take this second lockdown seriously," reported The New Zealand Herald.

Early April marked the peak of the first wave of the COVID-19 pandemic.

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