Immediately after shooting finished on Paris When It Sizzles, Audrey extended her lease on the Bourbon chateau she had been renting when the irresistible opportunity to star opposite Cary Grant in the Paris-based Hitchcockian comedy-thriller Charade turned up on her doorstep. The screenplay had been written specifically with Grant and Hepburn in mind, though Grant was at first reluctant to accept the part due to their 26 year age difference, having previously turned down the part of her love interest in Love In The Afternoon for the same reason. Together with screenwriter Peter Stone, Grant made revisions to the script to flip the romantic dynamic and make Audrey, as recent widow Reggie Lampert, do all the chasing, highlighting the age gap as part of the comedy with witty lines such as I could already be arrested for transporting a minor above the first floor.

The delightful film is packed full of tricks, twists and double bluffs, following Reggie's slow realisation that her late husband was a liar and a thief, as she is routinely terrorised by his one-time criminal associates in their search for the money they stole from the U.S. government during the war, while all the time kept bouyant by the flirty repartee and developing romance between Hepburn and the identity-shifting Grant who comes to her aid as Peter Joshua, Alex Dyle, Adam Canfield and finally Brian Cruikshank.

With a dream cast, witty dialogue, chic setting and thrilling storyline, Charade was Hepburn's biggest hit yet, hailed by The New Yorker as the best American film of the year.