Sir Keir Starmer has gone into self-isolation after a family member showed symptoms of coronavirus.
It means Sir Keir will not be able to speak in today’s Commons debate and will have to work from home.
It was announced shortly after the Labour leader took part in his monthly LBC show, Call Keir. His office have contacted LBC.
A spokesman for Sir Keir said: “This morning Keir Starmer was advised to self isolate after a member of his household showed possible symptoms of the coronavirus.
“The member of his household has now had a test. In line with NHS guidelines, Keir will self-isolate while awaiting the results of the test and further advice from medical professionals.”
It is understood Sir Keir has not shown any symptoms of the virus.
Mr Rees-Mogg was absent from the Commons during business questions on Thursday morning.
The father-of-six wrote on Twitter: “One of my children was tested for Covid-19 last weekend after displaying symptoms.
“In accordance with government guidance, the household has been in self-isolation while we await the test result.”
This afternoon, MPs will debate a key amendment to the UK Internal Markets Bill during its second reading. Shadow business secretary and former Labour leader Ed Miliband will fill-in for Sir Keir by responding on behalf of Labour.