A graduate of the Royal Academy of Dramatic Art, she worked with notable filmmakers like Peter Brook, Federico Fellini, Roman Polanski, Michelangelo Antonioni, and Claude Chabrol, as well as in several genre productions.

The family moved to England prior to the outbreak of World War II, and Yvonne enrolled in St Hilda's College, Oxford in 1946 to study Modern Languages, where she was known as "Tessa Scatcherd".

She played in productions of Macbeth and The Taming of the Shrew, and was photographed by Norman Parkinson as one of "The Young Look in the Theatre" for the January 1953 issue of Vogue.

[2] She made her film debut with a minor role in Anthony Pelissier's omnibus comedy Meet Me Tonight (1952).

In 1955, she starred in Michelangelo Antonioni's Le Amiche, which won the Silver Lion at the Venice Film Festival, and launched a successful parallel career in Italian cinema.