20 Things You Didn’t Know About Thunderball (1965)
3. “Do You Think She’s Worth Going After?” “I Wouldn’t Put It Quite That Way, Sir!”
Cubby Broccoli had initially wanted to cast a known actress as Emilio Largo’s mistress, Domino.
He was impressed by Julie Christie in Billy Liar (1963), but disappointed by her casual appearance and modest bosom when he interviewed her. He then successfully contracted Raquel Welch, but she withdrew to film Fantastic Voyage (1966). Faye Dunaway almost signed on to play Domino, but chose to make her big-screen debut in The Happening (1967) instead.
The filmmakers then considered over 150 lesser-known actresses, including Yvonne Monlaur (known for several Hammer Horror films in the early 1960s), Maria Grazia Buccella, Marisa Menzies, and Gloria Paul.
Kevin McClory suggested former Miss France, Claudine Auger who had learnt English whilst working as an au pair in Mill Hill, London and was married to French director, Pierre Gaspard-Huit. When she was cast as Domino, the novel's Italian leading lady, Dominetta Vitali became Dominique Derval to accommodate her French accent. However, it was subsequently decided that Auger’s deep voice was inappropriate for Domino and she was dubbed in post-production by Nikki van der Zyl.
Despite this, Claudine Auger performed most of her own underwater scenes as she was an excellent swimmer.