Marlon Brando, who played Mafia don Vito Corleone in “The Godfather,” is known for the famous line from the film: “Make him an offer he can’t refuse.”

But the Oscar winner refused an offer he shouldn’t have — from “Godfather” director Francis Ford Coppola, who’d hoped Brando would reprise the Corleone character as a young man.

In a previously unpublished May 1973 letter obtained by The Daily Mail, the famed auteur pleaded with Brando to play the role of the young Corleone in “The Godfather: Part II,” insisting that “the movie cannot be made without you.”

“Marlon, I respect you enormously; and if you told me that you did not want to do it . . . I would accept that, and never mention it again,” Coppola wrote.

After Brando, then 49, shot down the part, it went to Robert de Niro, who was then 30 and a rising star.

He won the Oscar for Best Supporting Actor for his portrayal and the film won Best Picture in 1975.