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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The Maritime and Coastguard Agency have released a 'horrifying' film showing what can happen if you fall into cold water after drinking.
Some of the teenagers caught up in a coach crash in France, have returned home. The coach was carrying 40 Gloucestershire teenagers.
An exhibition of 18 Gromit statues opens at Cribbs Causeway later in a Gromit Unleashed Homecoming event.