 Marcel's mother, Lindsey Brook was an actress and her father, Terry Marcel, is a television director; they divorced in 1995.Her older sister Kelly is a writer and actress who has appeared in both "Holby City" and "The Bill", but is now best known as the writer and executive producer of the television series "Terra Nova" They also have a younger brother, Luke.When she was twenty years old, Marcel was diagnosed with endometriosis, and it was also discovered that she had a blood clotting disorder