During her marriage to Prince Andrew the Duchess of York travelled everywhere in luxury cars accompanied by bodyguards. Even as a divorcee her hard work to has allowed her to maintain an enviable standard of living based around a £2.5 million pad overlooking Central Park in New York.
So imagine the surprise of passengers on a train from London's Victoria to Bromley South in Kent when Sarah hopped on for the ride.
Renowned for her down-to-earth attitude despite her royal connections, the Duchess has made it a personal mission to work with ordinary people.
Last year the mother of two visited Hull for a TV programme in which she helped a family living on a council estate change their eating habits on a limited budget. In the process she swapped her privileged existence for accomodation in a B&B popular with lorry drivers and dockers.
Soon the 49-year-old campaigner will attempt a similar project in Manchester, working with local residents to set up community initiatives in a deprived area.