Other celebrities recently signed up for the event, which takes place at Wembley Stadium on September 7, include Gethin Jones and Heroes actor Santiago Cabrera.
The event, which airs on ITV, features a football match between England and the Rest Of The World. Ant and Dec, Tim Lovejoy and Louise Redknapp will present the coverage.
Celebrities and former footballers will make up the teams, which are being managed by Harry Redknapp and Kenny Dalglish.
England's team includes Craig David, Angus Deayton, McFly's Danny Jones, Jamie Theakston and Gareth Gates. Westlife's Nicky Byrne, Alastair Campbell, Patrick Kielty, Brian Lara, Kenny Logan and Gordon Ramsay are in the Rest Of The World's squad.
Speaking about his involvement in the match, Fountain said: "I had a dream last night that me and Gordon Ramsay actually had a fight on the pitch!
"That's how excited I am about the game, I'm even dreaming about it! In my dream Gordon kicked me and the ref was in the middle trying to break it up. I'm hoping this is not a premonition!"