British Prime Minister Boris Johnson has tested positive for the novel coronavirus, becoming the first major world leader to fall victim to the pandemic that has brought the planet to a virtual standstill.

In a video posted on his Twitter page Friday morning, Johnson confirmed that he tested positive for COVID-19 after displaying “mild symptoms.” The prime minister said he will continue to lead Britain’s fightback against the virus while self-isolating at home in 10 Downing Street.

The virus has struck at the heart of the British establishment. On Wednesday, the heir to the throne, Prince Charles, confirmed he had also tested positive for the coronavirus. It’s not immediately clear if Johnson has had recent contact with Charles or the 93-year-old Queen Elizabeth, whom the prime minister normally meets face-to-face each week.

Britain’s health secretary, Matt Hancock, has also confirmed that he has tested positive for the virus after showing “very mild” symptoms.

British newspapers reported that Johnson chaired the routine morning meeting on Britain’s coronavirus response via video link on Friday, and that several members of the government were told that they would have to self-isolate if they had been in contact with Johnson recently.

In his tweet confirming his diagnosis, Johnson wrote: “Over the last 24 hours I have developed mild symptoms and tested positive for coronavirus. I am now self-isolating, but I will continue to lead the government's response via video-conference as we fight this virus. Together we will beat this.”

He didn’t say if his pregnant fiancée, Carrie Symonds, had also been tested.

The prime minister was last seen in public Thursday night, when he stood outside the famous black door in Downing Street and joined people around the country in a round of applause for people who work in Britain’s universal health-care system, the National Health Service.

Health secretary Matt Hancock confirmed his diagnosis Friday afternoon in a self-shot video from home, similar to Johnson’s. Hancock said he’s only experiencing “very mild” symptoms and vowed to keep working from home and “driving forward Britain’s response” to the pandemic.

Earlier this week, Johnson told the nation it will be in virtual lockdown for at least three weeks, with only essential trips out of homes being allowed. Britain has just under 12,000 confirmed cases of the coronavirus as of Friday morning, and 580 people have lost their lives to the infection.