Eight celebrities, all with differing beliefs and faiths, put on backpacks and walking boots, and set out to cover the Italian section of the ancient 2,000km Via Francigena, which starts in Canterbury and finishes in Rome.
They have only 15 days to tackle 1,000km, so they start their pilgrimage in the Alps, just before the Swiss-Italian border. Will this journey of a lifetime change the way they think about themselves and their beliefs?
Actors Les Dennis and Lesley Joseph, professional dancer Brendan Cole, comedians Stephen K Amos and Katy Brand, Olympic long jump champion Greg Rutherford, Irish Eurovision Song Contest winner Dana and television presenter Mehreen Baig live as modern-day pilgrims.
They stay in basic hostels, sleep in shared dorms and follow a largely untrodden route, which is currently in the throes of revival. With just over two weeks to complete their pilgrimage, the eight pilgrims walk sections of the Via and travel some of the route by minibus.
When they reach the final 100km, they have to walk every step of the way. In this first episode, the intrepid eight arrive in Martigny, Switzerland, and find out for the first time who will be sharing their pilgrim adventure.
The series is narrated by Lee Ingleby.
Pilgrimage: The Road to Rome premieres this Sunday ,21 March at 9.30pm on ABC TV PLUS and iview