Team Cox will pound the streets of Bordeaux, while eating and drinking wine at various pit stops throughout the gruelling 26.2-mile race, on Saturday.
The team includes Peter Richards MW, Susie Barrie MW, Lynne Cox, Eduardo Chadwick, Francisco Baettig, Andres Izquierdo, Alvaro Arriagado, Greg Sherwood MW, Richard Dare and Vicky Thompson.
Twin brother David Cox, chief executive of the charity, will Tweet from the sidelines.
There is still time to donate at https://www.justgiving.com/teams/teamcox.
All money raised will go to members of the drinks industry that have fallen on hard times.