She was born on 5 October 1933 in Mooloolaba, Queensland. Her parents were medical practitioners Sir Raphael Cilento and Phyllis, Lady Cilento. At an early age, she decided to be an actress. She graduated from Royal Academy of Dramatic Art, London and moved to England in the early 1950s. Cliento began to have roles in British movies. She went on to win international acclaim as an actress during the 1950s and 1960s. 