Cary Grant was committed to doing another movie and was intent on retiring from films (again) when director Alfred Hitchcock offered him the chance to play an American scientist who appears to be defecting to the Soviets.

Perkins was suggested to Universal Studios by Alfred Hitchcock himself for the male lead in "Torn Curtain", but the studio preferred box-office champ Paul Newman.

Alfred Hitchcock wanted to cast his "North by Northwest" star as the female lead of his 50th film.