He was the king of lycra in the Nineties, but Mr Motivator will be donning a nurse's outfit to warm up the competitors for the Bristol half marathon.

The 56-year-old grandfather, one of the most famous fitness instructors in the country, will be making sure the 16,000 people taking part in the race will be raring to go when he takes the stage to lead the warm up.

Rather than his trademark fluorescent all-in-one he will be dressed as a nurse to encourage as many people as possible to run for cancer charity CLIC Sargent.

Mr Motivator, whose real name is Derrick Evans, flew into the UK from his home in Jamaica yesterday.

He said: "This will be my second visit to Bristol. I'm looking forward to it. I'll be doing 15-minute warm-up and we may include a bit of a sing-a-long in there. I'll be dressed as a nurse.

"Although I'm a good-looking man, dressed as woman I look really ugly, but I'll do anything for a laugh, thankfully I've got good legs. I support CLIC because this is a great way to help and support people with cancer. My wife's side of the family has had history of cancer, both her father and mother.

"Dressing up as a nurse and raising funds is a good way of drawing attention to an important cause. "

Mr Motivator shot to fame in the early Nineties promoting health and fitness on television show GMTV. A string of DVDs, exercise equipment and clothing followed. He also operates an eco-tourism company with his family in Jamaica.

Earlier this year he returned to GMTV for a three-week stint as part of its Get Motivated fitness campaign and has since even met with Gordon Brown to discuss health policies.

Yesterday he said he offered his last-minute tips for runners of this weekend's 13.1-mile course.

He said: "We'll just have fun, it's not a race. Make sure you stay hydrated, find a friend to jog with, have a laugh and we'll have a great day."

The Bristol Half Marathon is the start of CLIC Sargent's marathon journey leading up to next year's Virgin London Marathon of which CLIC Sargent is an official charity.

A new initiative will mean runners crossing the finish line will also be given useful advice on their journey home from the Highways Agency.

Isobel Lewis, of the Highways Agency, said: "The sort of live traffic data we now provide on the web, mobile phones and digital radio can be really valuable to people travelling to sports events all over the country."

Traffic information will be included in the runners' goody bags. For more information visit www.bristolhalfmarathon.com.