Health Secretary Matt Hancock has tested positive for coronavirus.
The announcement comes shortly after the Prime Minister confirmed he had also been diagnosed with the virus.
Mr Hancock said his symptoms so far had been mild, adding he would be working from home and with "no less gusto".
"Following medical advice, I was advised to test for coronavirus," he said in an announcement.
"I‘ve tested positive. Thankfully my symptoms are mild and I’m working from home & self-isolating. Vital we follow the advice to protect our NHS & save lives."
In a video message from his home, he said: "I'll be continuing to do everything I can to get our carers the support that they need.
"I'll be doing that from here but with no less gusto."
Shadow health secretary Jonathan Ashworth was among those to send messages of support to Mr Hancock.
He tweeted: “Take care and get well soon Matt. Look after yourself and best wishes to you and your loved ones.”
After the PM's and Mr Hancock's test, it is unclear if other high-profile figures they have had contact with are being tested.
Asked whether the chief medical officer or any other senior ministers have been tested, the PM's spokesman said: “In Number 10 we have been observing the advice on social distancing…
“We have wherever possible been using video conferencing.”
He added: “We have been taking steps and following the same advice which we have given to the public.”
