The former rower will be actively involved in advising on policy issues and attending meetings where crucial decisions will be made.

Cracknell, who won gold medals as part of the coxless four in the 2000 Sydney and 2004 Athens Olympics, has since carved out a reputation for himself as an adventurer.

He came second the pairs division of the 2005–2006 Atlantic Rowing Race in "Spirit of EDF Energy", partnered by television partner Ben Fogle, crossing the line in just under 50 days.

Last December he set off again with Fogle and Ed Coats - the winner of a nationwide search- to take part in the inaugural Amundsen Omega3 South Pole Race.

The team traversed the 473.6 miles suffering frost-bite, infected blisters, dramatic weight-loss, pneumonia and exhaustion and came second only to a pair of Norwegian polar experts.

The BBC are currently airing a documentary on the team's progress on a Sunday evening and the series is accompanied by a book, "Race to the Pole"

Cracknell said: "I've seen first hand how powerful the Olympic and Paralympic Games are and I'm incredibly impressed with the ambition of the London 2012 team.

"Sustainability is something that is incredibly misunderstood - it's not just about saving trees or rescuing newts, it's about making profound and lasting difference in people's lives.

"The Games has the power to do that - and I'm only too pleased to be on board to help tell this story.

"I've also competed in Games so I also hope I have something  useful to bring to the table from an athlete's point of view."