William Conrad (The Killers, 1946) Burt Lancaster (Gunfight At The O.K. Corral, 1957) Kirk Douglas (Paths Of Glory, 1957) Ralph Meeker (The Naked Spur, 1953) James Stewart (The Man Who Shot Liberty Valance, 1962) Lee Marvin (The Big Red One, 1980) Mark Hamill - Luke Skywalker
I couldn't find anything quicker than two:
William Conrad (The Naked Jungle, 1954) Charlton Heston (The Three Musketeers, 1973) Christopher Lee - Count Dooku
Happy Birthday, Gwyneth Paltrow!