Gary Barlow and Chris Evans are helping raise money for Breast Cancer Care by driving the length of the UK in a pink Rolls Royce.
The one-of-a-kind automobile is supposed to resemble Lady Penelope's car from the Thunderbirds series, including 'FAB1' number plates.
Joining the famous entertainers are professor Brian Cox and Top Gear's James May, as they travel from Land’s End to John O'Groats together.
The charity ride was originally radio presenter Chris Evan's idea, who said about the initative: "FAB1 Million aims to raise a million pounds for breast cancer – it's as simple as that."
Once the journey is finished, the car will be available to hire to continue to raise funds for the charity
"You can hire the most famous Rolls-Royce in the world as the icing on the cake to whatever special event you are attending or celebrating, knowing that you are donating to a very worthy cause in the process. It's a win-win situation," commented Evans.
Their progress can be followed on the @FAB1Million Twitter account.