欧洲某国的安妮公主(奥黛丽·赫本 Audrey Hepburn 饰)到访罗马,国务烦身,但她又厌倦繁文缛节。一天晚上,身心俱疲的她偷偷来到民间欣赏夜景,巧遇报社记者乔(格里高利·派克 Gregory Peck 饰)。二人把手同游,相当快乐。公主更是到乔的家中作客并在那过夜。 不料乔无意中发现了公主的真实身份,他决定炮制一个独家新闻,于是乔和朋友、摄影师欧文(埃迪·艾伯特 Eddie Albert 饰)一起带公主同游罗马,并且偷拍了公主的很多生活照。然而,在接下来与公主的相处中,乔不知不觉恋上了公主。为了保护公主的形象,乔只能忍痛抛弃功成名就的良机,将照片送予了公主。 安妮公主在经历了罗马一日假期后,反而体验了自己对国家的责任,毅然返回了大使馆,为了本身的责任而果断抛弃了爱情。Joe Bradley is a reporter for the American News Service in Rome, a job he doesn't much like as he would rather work for what he considers a real news agency back in the States. He is on the verge of getting fired when he, sleeping in and getting caught in a lie by his boss Hennessy, misses an interview with HRH Princess Ann, who is on a goodwill tour of Europe, Rome only her latest stop. However, he thinks he may have stumbled upon a huge scoop. Princess Ann has officially called off all her Rome engagements due to illness. In reality, he recognizes the photograph of her as being the young well but simply dressed drunk woman he rescued off the street last night (as he didn't want to turn her into the police for being a vagrant), and who is still in his small studio apartment sleeping off her hangover. What Joe doesn't know is that she is really sleeping off the effects of a sedative given to her by her doctor to calm her down after an anxiety attack, that anxiety because she hates her regimented life where she has no freedom and must always do and say the politically correct things, not what is truly on her mind or in her heart. In wanting just a little freedom, she seized upon a chance opportunity to escape from the royal palace where she was staying, albeit with no money in her pockets. Joe believes he can get an exclusive interview with her without she even knowing that he's a reporter or that he's interviewing her. As Joe accompanies "Anya Smith" - her name as she tells him in trying to hide her true identity - around Rome on her incognito day of freedom somewhat unaware that the secret service is searching for her, along for the ride is Joe's photographer friend, Irving Radovich, who Joe has tasked with clandestinely taking photographs of her, those photos to accompany the story. As the day progresses, Joe and Ann slowly start to fall for each other. Their feelings for each other affect what both decide to do, Ann with regard to her royal duties, Joe with regard to the story, and both with regard to if there is a future for them together.