The Duke of Cambridge reportedly tested positive for the virus just after his father, Prince Charles, and British Prime Minister Boris Johnson came down with COVID-19 the same month.

Prince William "struggled to breathe" as he was fighting the coronavirus disease in April, the Sun newspaper reported.

"William was hit pretty hard by the virus - it really knocked him for six", a source told the Sun. "At one stage he was struggling to breathe, so obviously everyone around him was pretty panicked."

The Duke decided to keep his diagnosis in secret in order not to cause panic among the Britons at that time, as Europe was going through a difficult period combating the pandemic. "There were important things going on and I didn't want to worry anyone", he reportedly said at an engagement, as Queen Elizabeth had just delivered words of encouragement to the nation on the decisive fight against the pandemic.

After catching the virus, the Duke received medical treatment and then isolated at Anmer Hall, in Norfolk, but continued to receive phone and video calls while in quarantine. "He was determined to fulfil his engagements", the source said.