Mister Jericho

This was originally a pilot episode for a television series, and stars Patrick Macnee as Dudley Jericho, a suave and charming conman who sets out fo rob corrupt millionaire Victor Rosso (Herbert Lom), of his famous Gemini diamond. Rosso is obsessed with obtaining the stone's twin, and so Jerico obtains a perfect copy of the stone as part of his plan to swindle Rosso, but before he can start the con a woman from Paris called Mademoiselle Claudine (Connie Stevens) appears, claiming she has the twin Gemini diamond. Rosso knows that one of them is lying, but which one?