A Funny Thing Happened on the Way to the Forum is a 1966 period musical comedy film directed by Richard Lester, based on the stage musical of the same name with music and lyrics by Stephen Sondheim, and book by Burt Shevelove and Larry Gelbart. It stars Zero Mostel and Jack Gilford, reprising their roles from the Broadway stage production. It also features Buster Keaton in his final screen role; Phil Silvers, for whom the stage musical was originally intended; and regular Lester collaborators Michael Crawford, Michael Hordern, and Roy Kinnear.