Isabella Calthorpe was born on March 3rd 1980, daughter of property developer John Austen Anstruther-Gough-Calthorpe and socialite, débutante and banking heiress Lady Mary-Gaye Georgiana Lorna Curzon. She has one full sister, Georgiana, and one full brother, Jacobi, as well as four half sisters, Pandora, Gabriella, Cressida and Octavia. Isabella who directly descends from King Charles II is blue blood to the core. She went to finishing school in Switzerland, studied classics at Edinburgh University and attended the London Academy of Music and Dramatic Art 2003 to 2005. She has appeared in film as Anna in How to Loose Friends and Alienate People and in Richard Eyre's Stage Beauty. On Television she has played Emily in the BBC production of Inspector Lynley as well as Miranda Cost in the British television series Harley Street. As a stage actress she had attracted rave reviews as Lisa in Dirty Dancing at the Aldwych and previously played in Peter Gill's The Voysey Inheritance at the National Theater and as Cecily in David Leonard's The Importance of being Earnest at the Royal York. She has been dating heir apparent Sam Branson, son of Virgin owner Richard Branson for almost three years.

Sister Gabriella 18 is a supermodel with regular appearances in Vogue.In December 2007 she shared second place with her sister Gabriella in Tatler's socially prestigious list of the most eligible girl in Britain. Princess Diana's niece Lady Kitty Spencer, daughter of Earl Spencer took first place, with actress Sienna Miller in third place.She attended LAMDA where Alumni include Stacy Keach (ER and Prison Break) and Jim Broadbent (Harry Potter 6).Her fourth cousins are Prince William and Prince Harry.Her maternal grandfather Lord Curzon was a racing driver in pre-war Britain.