Gary Barlow, Chris Evans, James May and Brian Cox have set off from Lands End in a pink Rolls Royce raising money for Breast Cancer Care.
The challenge will see them driving from Land's End to John O'Groats in a bespoke pink Rolls Royce Ghost.
They want to try and raise £1 million in 24 hours.
The four celebrities will stop off in Bristol as part of their trip.
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Six of the small marsupials have been born in the 180-year-old Zoo’s Twilight World and keepers say they are thrilled.
A cloudy night will have drizzly spells throughout and into the early hours.
It will be a largely cloudy night with outbreaks of light rain. There will also be some hill fog.