Her heyday came in the late Fifties and Sixties, with her most memorable film part being that of Molly Seagrim, the lewd gamekeeper's wench in Tony Richardson's 1963 production of Henry Fielding's Tom Jones.
The role earned Diane an Academy Award nomination for best supporting actress, but by then she had married Connery, the man who, in the view of many, came to define her own life. Certainly her fame blossomed after she married him in 1962.
"He walked with the peculiar forward-leaning, slightly pigeon-toed gait of a body builder," she recalled, "and his thick eyebrows met between his eyes. He looked dangerous but fun."
Their union proved rich, gossip-column fodder. In her autobiography My Nine Lives (2006), Diane claimed that Connery insisted she give up her career and, when she refused, turned petty and violent. Word went out, she wrote, that he would never work with anyone who employed her, and he stopped her housekeeping money.
She realised the marriage was over, she added, when Connery "bashed my face in with his fists".
The alleged assault in 1965 echoed an infamous interview Connery had given to Playboy magazine earlier that year in which he observed: "I don't think there is anything particularly wrong about hitting a woman -- although I don't recommend doing it in the same way that you hit a man.
"An open-handed slap is justified -- if all other alternatives fail and there has been plenty of warning. If a woman is a bitch, or hysterical or bloody-minded continually, then I'd do it."
Connery has always insisted that his words were taken out of context, and also denied hitting Diane.
Her own version of events was recounted by the author Geoffrey Wansell in his 2001 biography of Connery.
She had been chatting to a waiter in a bar in Spain. A furious Connery, she claimed, took her to their room and punched her between the eyes with his fist, then hit her in the face repeatedly until she collapsed unconscious. Her face, she told Wansell, ballooned out "like a giant puffer fish" and a blood clot formed in one eye for six weeks.
The beautiful Oscar nominee was terrified that she had lost her looks forever and would never work again.
Although she came to regard Connery as a monster, she put her marital woes behind her. "I could hear my mother's voice in my ears: 'There's nothing less attractive than a moaning, whining woman, Diane'," she wrote.
She and Connery divorced in 1973, and two years later Diane returned to her native Australia to build and run a theatre, the Karnak Playhouse, in Queensland. She also had a spiritual awakening, and later recounted how the Tamil sage Bawa Muhaiyaddeen helped her in her quest to be at one with God.
Diane Cilento was born on October 5, 1933, in Brisbane, the daughter of two prominent medical practitioners, Sir Raphael (Ray) and Lady (Phyllis) Cilento. Her brilliant but eccentric father rid northern Australia of malaria and typhus, while her forthright and controversial mother wrote newspaper medical columns and was accused of quackery for her early advocacy of the use of vitamin supplements.
Expelled from her private school in Brisbane at 15, Diane lived with her father in New York and joined a touring theatre company playing children and working as an assistant electrician. A scholarship to Rada took her to London, where for three seasons she was a resident player at the Royal Court. Minor roles in British films provided her with steady work until the end of the 1950s.
In 1956, she was nominated for a Tony award for her portrayal of Helen of Troy in Jean Giraudoux's play Tiger at the Gates.
After Tom Jones and, the following year, The Third Secret, she was Caterina de Medici, the love interest for Charlton Heston in The Agony and the Ecstasy (1965), and starred with Paul Newman in Hombre (1967).
But as her marriage to Connery continued, her film career declined.
In 2008, Diane alleged that Connery was not planning to leave a penny of his fortune to their son, Jason. "Sean has a problem about relationships," she said, "as everyone around him knows." Connery rattled out his response: "Diane is insane."
In 2001, she was awarded the Australian Centenary Medal for "distinguished service to the arts, especially theatre".
Diane married Andrea Volpe in 1956, with whom she had a daughter. The marriage was dissolved in 1960 and she married Connery two years later.
In 1985, she married the playwright Anthony Shaffer, who wrote the script for the horror movie The Wicker Man (1973); she met him when she appeared in the film as the teacher, Ms Rose. Shaffer died in 2001.