Sheffield MP Harry Harpham is undergoing treatment for cancer.
Mr Harpham - who won the seat of Sheffield Brightside and Hillsborough for Labour at the General Election in May after more than a decade as a city councillor - was diagnosed around two months ago.
The politician, who has not disclosed the type of the disease he has developed, is on a course of chemotherapy at Weston Park Hospital.
But he said he is still ‘functioning properly as an MP’ and meeting all of his commitments to his constituency.
“I don’t want to make a big song and dance about it,” he said.
Mr Harpham, aged 61, said he felt ‘fine’ leading up to the election, but then suffered ‘pains’ for two to three months after polling day.
He visited his GP at Firth Park Surgery, then underwent scans which led to the diagnosis at the end of September.
“I was diagnosed the Friday after party conference,” he added. “Obviously I have let the national Labour Party at Westminster know. Both of my offices are functioning 100 per cent - both my London office and my Sheffield office. Obviously I am delegating bits of work as I need to get on an even keel with my treatment.
“I’m going to work still, and working a lot from home. My surgeries are still running with the help of my staff and I am still meeting all of my commitments. To my constituents, which is the most important thing, I’m still available. I’m still functioning properly as an MP, but I’ve got this health issue that is, at the moment, interfering with my life.”
Mr Harpham said he did not know how long his treatment would last.
“Everybody reacts to chemotherapy differently,” he said.
However, he praised the ‘fantastic’ standard of care he has received so far at Firth Park Surgery, and the Northern General and Weston Park Hospitals.
“It’s one of the reasons I feel so strongly about the NHS and keeping it free at the point of use. I’m very proud of it and this has just reinforced what a brilliant asset it is to this country. It is the best health system in the world.”
Mr Harpham, a former miner, represented Manor and Darnall on Sheffield Council, and also held the post of Deputy Leader before succeeding David Blunkett as MP for Sheffield Brightside and Hillsborough.