There is no simple answer to the question of who Jane Birkin is. For the past 50 years, she has been hailed as a Bohemian sex goddess and a symbol of libertinism. A leading figure of the Swinging London scene, Birkin appeared as a naked nymphet in Michelangelo Antonioni’s Blow-Up (66). In Paris, she came to full blossom in her collaborations with another provocateur—her longtime partner, poète maudit Serge Gainsbourg.

Gainsbourg triggered a startling metamorphosis in Birkin, transforming her from a young ingénue into the epitome of uninhibited female bravura. Jane occupies a profound place in Serge’s oeuvre: she is not merely his muse; she becomes the work itself. Determined to unleash what he called “Jane’s exceptional dramatic potential”, Gainsbourg penned a script for her in 1975. With Je taime moi non plus, he presents his Galatea in a radically different light, inventing her as an actress and reinventing her as a woman.

Set in a washed-out wasteland reminiscent of Arizona’s rusty deserts, this quasi-apocalyptic tale charts a brief but tormented passion between two lost souls: macho gay truck driver Krassky and androgynous waitress Johnny. Repeatedly thrown out of hotel rooms because of Johnny’s “orgasmic excitations,” the couple resorts to open air lovemaking. In the lustful, bitterly poignant penultimate sequence, the meaning of the film crystallizes in Krassky’s unforgettable climactic lines.

Playing Johnny was a physically arduous experience for Birkin, who immersed herself in the role to an agonizing degree. At the end, her raw, feral performance reaches cathartic heights as she becomes some sort of Christian martyr, destroyed by her passion. In front of Gainsbourg’s camera, Birkin imparts an immediacy and a truthfulness in her performance that makes her whole being accessible to us. Like a Pygmalion, Gainsbourg has carved a mannequin into a woman, and the woman, patiently, has carved herself into an artist.

In 1981, Jacques Doillon, one of the more cerebral French filmmakers of the time, entrusted Birkin with a role of a rare psychological intensity. In The Prodigal Daughter, Birkin is Anne, a troubled woman who returns to her parents’ house to overcome her depression. Afflicted with an Electra complex, Anne takes advantage of her mother’s absence to create an emotional vacuum around papa and lure him into her incestuous web.

Birkin’s performance as Anne is strikingly multifaceted: she goes from being a demoniac temptress in one scene to an innocent child in need of paternal warmth in the next, effortlessly transitioning between emotional extremes. On set, Doillon would stand close to his actress and whisper the lines to her while the camera was rolling. This simultaneity of direction and performance creates an uninhibited synergy between the filmmaker and the actress, binding them into one body, as it were. Birkin embodies Doillon’s angst. She becomes his film.

The Prodigal Daughter was a pivotal moment in Birkin’s filmography, establishing her as an actress of exceptional intellectual caliber. For the first time, she had exposed her naked self without exposing her naked body. In the years to come, Birkin redefined herself as an artist who could function independently of Gainsbourg’s creative control, and multiplied daring, transcendental parts, which paved the way for her daughter Charlotte’s equally intrepid career.