Astronaut Tim Peake is urging runners on Earth to join him as he trains for the London Marathon in space.
The Briton is pounding out the miles on a treadmill aboard the International Space Station (ISS), which is about 200 miles over the Earth, as he is set to become the first man to run a marathon in orbit on April 24.
To help with the challenge Peake, 43, is using the Digital Virgin Money London Marathon for some of his training runs and will be tweeting the times of his training runs on @astro_timpeake, which will be retweeted by @LondonMarathon.
Peake, who is running the 26.2 mile marathon to raise awareness for The Prince's Trust, said: "It can be lonely pounding out the miles on the treadmill in the ISS.
"It would be fantastic to run with other people and see their avatars on my screen as I do my training. Only 50 days to go now!"
The first chance to train with him will be on March 13 at 10am.
Peake has a strict fitness regime while he is on his six-month mission as astronauts need to combat the impact that microgravity can have on their bone density and muscles.
Virgin Money London Marathon event director Hugh Brasher said: "Millions of people all over the world are following Tim's mission in space.
"Now is the chance for runners to train with him and help him as he prepares for this extraordinary marathon on the International Space Station."
Peake, Britain's first official astronaut, will not be the first person to run a marathon in orbit.
This feat was achieved by US astronaut Sunita Williams who completed the marathon distance on a treadmill in 4 hours 23 minutes and 10 seconds on the same day as the Boston Marathon in April 2007.