Wales' First Minister Mark Drakeford is self-isolating after coming into contact with someone who has tested positive for Covid-19.
He began self-isolating for 10 days on Monday.
A Welsh Government spokesperson said it was a "precaution" and said he had tested negative for the virus.
The news emerged as Mr Drakeford gave evidence from home to the Welsh Affairs Select Committee of MPs on Thursday afternoon.
People are required to self-isolate for 10 days if they are asked to by contact tracers.
The first minister is the latest senior British political figure to have to self-isolate during the pandemic.
Prime Minister Boris Johnson contracted Covid-19 during 2020, and was treated in hospital. Labour leader Sir Keir Starmer has had to self-isolate three times.
Both Mr Drakeford's wife and mother caught coronavirus last year.
He said he moved out of his home into a building in his garden to keep his family safe.
"On a purely personal level, both my wife and my mother fell ill with coronavirus at a point where I was not able to live at home because they were both vulnerable," he said.