Martin Landau...

In North by Northwest, James Mason's Vandamm does not want for minions, and almost all of them survive to the climax on Mount Rushmore. But Leonard is the one you remember - ever present, usually just behind Vandamm, invariably staring at him, often wearing a matching suit. That last was Hitchcock's idea - that Leonard should have smarter suits than Cary Grant's character. Don't ask me why: It's just one of those small details the director liked to throw in to prevent your assumptions about characters getting too predictable. So he sent the actor to see Grant's tailor, Quintino of Beverly Hills. A couple of weeks later, Landau arrives to shoot his payphone moment at LaSalle Street Station in Chicago, and gets there in the middle of Cary Grant's scene. So he stands in the middle of a crowd of Chicagoans who are watching all the comings and goings. He's hardly been there a few minutes when there's a tap on the shoulder, and he turns to find Grant's English valet behind him. "Only two people in the world make a suit like that," the guy says, unaware that Landau's in the film. "One's in Beverly Hills, the other's in Hong Kong. Mr Grant wants to know where you got yours."

In the midst of his scene with Eva Marie Saint, Cary Grant had somehow contrived to spot the only fellow in the crowd in a better suit than his.