Olympic marathon runner Rebecca Cheptegei is in hospital after she was allegedly set on fire by a former lover.

The 33-year-old Ugandan athlete reportedly received burns to 75 per cent of her body in the incident.

Reports say Cheptegei was in Kenya after the Olympics, and the alleged attack happened in her house in the western Trans Nzoia County.

Trans Nzoia County Police commander Jeremiah ole Kosiom said the incident happened after Cheptegei had a disagreement with her ex-boyfriend, Dickson Ndiema.

Ole Kosiom said Ndiema then bought a can of petrol and allegedly poured it on Cheptegei.

Ndiema is also suffering from injuries from the incident.

Local reports say neighbours came to the rescue to help douse the flames.

A five-litre jerry can was found near the scene, according to reports.

Ndiema and Cheptegei are reportedly both in the same hospital, the Moi Teaching and Referral Hospital in Eldoret city.

Cheptegei placed 44th in the marathon in Paris.

According to her parents, she bought property in the area to be close to Kenya’s top training facilities and athletes.

She was already in training for her next event.