Donen’s charming comedic thriller stars two of Hollywood’s most elegant stars at the very top of their game and visibly enjoying themselves – and each other – as they sleuth through the photogenic Paris streets. When Hepburn’s widow is hunted by an unlikely trio of American thieves who believe she has a jinxed treasure stolen from them by her husband, she turns to Grant for comfort – but can he be trusted? It was apparently Grant who, worried by the age difference between them, suggested Hepburn be the pursuer in their relationship, resulting in their own cat and mouse game, and her memorable pick-up line, “You know what’s wrong with you? Nothing.”