Diana Scott, [Julie Christie], is a bored young model married to Tony Bridges [T.R. Bowen]. One day, she is spotted on the street by a roving film crew and interviewed about young people’s views on convention by Robert Gold, [Dirk Bogarde], a literary interviewer and television arts programme director. He invites her to watch the final edit in the TV studio, and there their relationship begins. After a series of liaisons in hotel rooms, they leave their spouses (and, in Robert’s case, his children) and move into a shared apartment.
As a couple they drift into the fashionable London media and arts set, where Diana’s appeal opens doors she hadn’t imagined. At first she feels a twinge of jealousy when Robert visits his wife as she sees their children, but that feeling fades as she finds herself drawn to a world built on influence, glamour, and spectacle. A pivotal figure emerges in Miles Brand, [Laurence Harvey], a powerful advertising executive at the Glass Corporation, who helps her land a part in a glossy but trashy thriller after she consents to have sex with him. Meanwhile, Robert—more bookish and seeking quiet—begins to feel increasingly jealous, then detached and lonely as the couple becomes more entwined with the industry’s social whirl.
Diana’s public life balloons when she is chosen to front a high‑class charity draw for world hunger, a event staged with giant images of famine victims that sits in stark contrast to the guests who gorge themselves. She later discovers she is pregnant and makes the painful choice to have an abortion in order to preserve her career and public image.
Her jet‑set appetite carries her to Paris with Miles, where the party scene operates like a vivid mind game—wild parties, loud music, flirtations, cross‑dressing and mind games that repulse her at first but then begin to command her respect as she taunts Miles in one of the games. On her return to London, Robert publicly brands her a whore and leaves her, while Miles casts her in a new, conspicuously glamorous advertising role as “The Happiness Girl” for a chocolate brand.
Diana then finds a different kind of companionship in Malcolm, a gay photographer who outfits her new look and helps her navigate this next phase of fame. They go shopping together, and she even indulges in a shoplifting impulse during a day out. On location at a palazzo near Rome, Diana smiles in a Medieval/Renaissance costume and completes the shoot for “The Happiness Girl.” She is enchanted by the palazzo’s beauty and the surrounding landscape, and she forms a cordial rapport with Cesare, the prince who owns the place, played by José Luis de Vilallonga.
Cesare visits in a grand launch, invites Diana and Malcolm aboard, and proposes marriage. She declines, though the door is left open. When she returns to London, she still oscillates between the allure of the Catholic church she sometimes pursues and the lure of rich, empty gaiety, but the romance with Miles has cooled and the fling with Cesare remains an option rather than a life plan.
Back in the capital, Diana hosts a party with Miles and the rest of the media crowd. Robert comes by and sees her with Miles, and he leaves, reinforcing the sense that she’s adrift between two incompatible worlds. Feeling disillusioned with the jet‑set life, Diana once again turns toward the church, then impulsively flies to Italy and marries Cesare. The marriage proves ill‑fated: Cesare treats her as a pampered mistress rather than a partner and eventually abandons her at the vast palace.
Diana returns to London to see Robert, and the two briefly rekindle a physical connection, raising hope for something lasting. But Robert reveals that he intends to leave her again and drives her to Heathrow, preparing to return her to her life as Princess of Della Romita in Rome. At the airport, the press crowd surrounds her, calling her by her royal title, and she boards the plane, accepting that her life is now a perpetual performance between two continents, two loves, and two identities.
