Allen said the large sand dunes in the Sahara would be “the biggest challenge, especially in the likely temperatures”.
Sahara desert temperatures can reach 40C during the day and drop to 0C overnight.
Allen will be joined by his son, James, and led along the route by Berber tribesmen.
Megan Smart, from Prostate Cancer Research, said the charity was “totally inspired and just motivated” by Allen and aimed to support him as much as possible.
The money raised would help “change that future for men” with prostate cancer, said Smart.
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