Her mother is an English dancer and her father an Italian painter. She grew up in Milan and later moves to London. In 1975, her parents moved to Australia, and Greta worked as a cowgirl and an Italian interpreter. At age 18, she returned to London and followed lessons at the Old-Vic-Theatre. Played small parts as a stage actress and worked as a model for commercials. The young film maker Dominik Graf discovered her and her first film part is Zweite Gesicht, Das (1982). Being a perfectionist, she learned German for this movie. After Heat and Dust (1983), she played parts for Australian and English television and returned to London. While playing in a modernised play by Anton Chekhov in 1988, (directed by Margarethe von Trotta), she was discovered by Hollywood.