Health minister and Conservative MP Nadine Dorries says she has tested positive for coronavirus.
She said in a statement that as soon as she was informed she took all the advised precautions and had been self-isolating at home.
It comes as a sixth person died from the virus in the UK, which has a total of 382 cases.
The latest person to die was a man in his early 80s who had underlying health conditions.
GPs are warning that routine appointments at surgeries may have to stop as the number of coronavirus cases rises.
The British Medical Association said routine monitoring of long-term health conditions might have to stop to enable GPs to “focus on the sickest patients”.
Ms Dorries said in a statement she took “all the advised precautions” as soon as she was informed of her diagnosis.
She added: “Public Health England has started detailed contact tracing and the department and my parliamentary office are closely following their advice.”
Health Secretary Matt Hancock tweeted that she had “done the right thing” by self-isolating at home and wished “her well as she recovers”.
He added: “I understand why people are worried about this disease. We will do all we can to keep people safe, based on the best possible.