Many thanks to all of you who have sponsored him so far! If you have been meaning to make a donation but haven't got round to it, there's still time....Please click on this link to his JustGiving page
If you want to know what he's let himself in for, then please read on....
It takes a lot of courage, bravery, grit and determination (or stupidity, according to Jack!) to do this feat especially if - like him - you are not a professional cyclist.
The distance is 146.5 kilometres; the steepest gradient is 8.5% and there are no less than four mountains to climb (and descend...the really scary bit)
Even the guys who do it for a living find it hard going! You can watch the professionals ride this stage of the Tour on Saturday 23 July.
Jack will be doing his cycle ride over exactly the same course on Sunday 10 July, along with team mates David Gillet and Gair McAdie.
Good luck Jack and the rest of the team!!
The pattern of recent Tours is followed with a major mountain stage in the Alps the day before the finish. This has a twist, however, as the finish is at the foot of one of the nastiest descents the Tour uses, the 14km of twists and turns off the Col de Joux-Plane. There are three earlier climbs before the final shootout, which will favour a sublime descender such as Vincenzo Nibali or Bardet rather than Froome.