30 miles a day, six days a week for seven weeks? Quite a feat of endurance running. The athlete? One Eddie Izzard.
To keep up to date, donate or see whether the UK comic is heading through your town, visit www.eddieizzard.com.
Here's what Eddie - star of the trulyy great Mystery Men comedy - had to say on the challenge...
"Sport Relief, the Sporty part of Comic Relief asked me (and probably a lot of other people) if I would like to do a sporting challenge.
I had always wanted to do a big physical running challenge, and this seemed a great way to do it and also raise money to help Africa and the poorest countries in the world as well as projects that Sport Relief fund in the UK I was also going to be advised by Olympic experts who have worked with Sport Relief before. They would help me keep running in the right direction.
So I told them I wanted to try to run around the whole of the UK. London to Cardiff to Belfast to Edinburgh and back to London, running through as many parts of the UK that lie in between our 4 capitals.
They said great. You're nuts.
I said yes but that never hurt.
They said how far is this?
I said 1100 miles. I will try to run 30 miles a day for 6 days a week. It will probably take 7 weeks.
They said great. Is there anything else you want to mention.
Yes. I will run through England holding and English flag and then I'll run through Wales holding a Welsh flag and so on through all the UK.
But why not just have a Union Jack?
Because this is the thinking for my mission:
WE ARE DIFFERENT
WE ARE THE SAME
WE ARE UNITED KINGDOM
WE ARE AFRICA
WE ARE HUMANITY
They said - anything else?"
