Leave.EU today announced it would hold a Run for Freedom event on 12 June at Wolverhampton Racecourse, featuring racing driver McCarthy alongside TV personality and ex-Olympic rower James Cracknell, and Leave.EU organiser and former Cracknell's teammate Alex Story.
Media will be invited and there will be a 5km fun run and walk to support the campaign for the UK to exit the European Union in the 23 June referendum.
The event will also feature Conservative, Labour and UKIP politicians cheering on the runners.
Story said: "Running for freedom is what this referendum is about. I was so proud to have represented this country as an Olympic athlete, because that is where my allegiance lay and it is why I am fighting for the UK to become a free sovereign nation again.
"My mother is Austrian, my wife German and I was raised in France where my father worked. I am multilingual and as cosmopolitan as you could possibly be. I love Europe, which is why I so object to the EU."
Double gold-medal-winning Olympian James Cracknell said: "We need to be fit to take on the world again. It won't be simple; there will be ups and downs but we have to do it."
Former Formula One driver McCarthy was The Stig between 2002 and 2003, keeping his identity secret for a number of years after.