Double Olympic gold medallist Dame Kelly Holmes will take part in the Great Manchester Run on 20 May.
Holmes won the 800m and 1500m at the 2004 Olympics in Athens
But the 36-year-old Briton, who retired after capturing 800m and 1500m gold at the 2004 Games in Athens, insists her competitive days are over.
"Remember I'm running for fun. I won't be lining up with the elite athletes, that isn't for me anymore," she said.
"I just want to go out there, enjoy the atmosphere and help encourage everyone else. I'm looking forward to it."
Organisers are delighted Dame Kelly will be running in the 10km road race, which has an entry of 28,000 runners.
"I think its brilliant news that she is managing to fit the BUPA Great Manchester Run into her very busy schedule," said communications director David Hart.
"I'm equally certain the masses who will join her along the route will get a special kick out of running alongside a truly great Olympic champion."