Olympic boss Lord Coe is to be a contestant on Who Wants To Be A Millionaire? - teaming up with former middle distance running rival Steve Cram.
The pair will take part in a "best of friends" special of the ITV quiz to be screened this month, which will also feature another Olympic star Louis Smith.
Bronze-medallist Smith - the victor in last year's Strictly Come Dancing on BBC1 - is to play alongside his gymnastic coach Paul Hall.
Lord Coe, who has been a friend of BBC commentator Cram since their competitive days on the track, said: "It is terrifying but at the same time I know it will be great fun."
Actress and presenter Sally Lindsay is also taking part alongside her partner, the rock drummer Steve White.
Each of the contestants will be raising cash for charity when they face question master Chris Tarrant.
Smith said: "It's always a scary feeling when you're playing with what could be someone else's money. For that reason I am grateful to be playing with my coach Paul.
"We've always spoken about how good he'd be on the show so it's great to have the opportunity to put that into practice and I can be there for moral support if nothing else."
The programme is to be screened on March 17.