Double Olympic gold medallist Dame Kelly Holmes is running the London Marathon for the first time and she was lucky enough to meet up with marathon world record holder, Paula Radcliffe.
Drinking tips during the run, as well as carb-loading and refuelling are some of the great hints that Paula offered Kelly.
If you want to see more of Kelly and Paula, you can catch up with 'Kelly Holmes: My marathon story' on the BBC iPlayer.
Kelly talks about her career in athletics, her battles with depression and self harming as well as the current state of athletics as well as her reasons for running the London Marathon.
If you fancy challenging yourself to a run why not have a look at our running page?