UNITED NEWS INTERNATIONAL (UNI) — A British man who collapsed while running in the London Marathon over the weekend has died in hospital.

Matt Campbell, age 29, went down at the 22.5-mile mark and was treated on the roadside before being admitted.

Campbell was a well-known face in the U.K. after being a contender on the BBC’s TV program, MasterChef. He also ran in the Manchester Marathon earlier this month and finished in under three hours.

His death was announced by the event organizers on Monday, April 23. His cause of death, however, is not yet known.

Sunday’s marathon was the hottest London Marathon on record, with temperatures around 24 degrees Celsius. London Marathon Race Director Hugh Brasher, however, told the Guardian it’s unclear if the heat was a factor in Campbell’s death.

Meanwhile, also running in this year’s race were the firefighters who worked on Grenfell Tower and the police officer who was stabbed in the London Bridge terror attack.