Prince William tested positive for coronavirus in April, according to reports.
The Duke of Cambridge caught the virus around the same time as his father, Prince Charles, Kensington Palace sources told the BBC.
READ MORE: England's new four-week coronavirus lockdown may have to last longer
He continued to carry out multiple video engagements during that time, the BBC said.
The Palace has not officially commented on his positive COVID-19 test.
Prince Charles revealed his diagnosis at the end of March.
He went into isolation with his wife, Camilla, in Scotland, after suffering mild symptoms.
The UK is this week returning to a second lockdown after a spike in COVID-19 cases.
The lockdown was announced on Saturday by Prime Minister Boris Johnson and is to run from Thursday until December 2.
Mr Johnson says it's needed to stop hospitals from becoming overwhelmed by COVID-19 patients within weeks.
He said that "no responsible prime minister" could ignore the grim figures.
Source: 9News https://www.9news.com.au/world/coronavirus-prince-william-diagnosed-covid-19-april-with-prince-charles/6fe1ca15-e878-4052-8ba3-7c3ef11570ba