Ziji Productions Former "MasterChef" contestant Matt Campbell died after running the London Marathon on Sunday. Campbell collapsed during the race and later died at the hospital. The exact cause of his death is unknown. Campell was running the marathon in memory of his father — who died 18 months prior — and to raise money for the Barathy Trust. Former "MasterChef: The Professionals" contestant Matt Campbell died after running the London Marathon on Sunday.