A FITNESS guru who has helped celebrities such as Chris Moyles, Cheryl Cole and John Bishop take on extreme challenges is set to compete in this year’s Ironman event.

A former modern pentathlete, professor Greg Whyte has competed in two Olympic Games and won European bronze and World Championship silver medals And although he has never competed in an Ironman triathlon before, he has taken part in other ultra endurance events such as Race Across America and swimming the English Channel.

He said: “Ironman is the blue riband of triathlon events.

“It requires incredible ability in three very different disciplines and a huge amount of training and commitment.

“It’s one of the toughest one-day races on the planet and I’m looking forward to experiencing the pain that I invariably inflict on others.”

Comedian David Walliams, who he successfully coached to swim the English Channel for Sport Relief in 2006, said: "I wasn't surprised when Greg told me that he'd signed up to do an Ironman.

“It's the kind of crazy thing he'd do just for fun and it's going to be fun seeing him suffer instead of me."

on Sunday, August 4, he will join a sell-out 1,800 athletes at the ninth annual Ironman UK, which sees participants swim in Pennington Flash and cycle through the Lancashire countryside before finishing with a looped marathon course cheered on by thousands of spectators in and around Bolton town centre.

His ambition is to gain one of the five qualifying places for the Ironman World Championship in his 45 to 49 age group, meaning he will need to complete the course in under 11 hours.

Ironman UK managing director Kevin Stewart said: "We are very much looking forward to welcoming Greg to this year's Ironman UK.

“It is great to see him taking up such a challenge having had so much success in helping other non-athletes achieve their goals.”