Keeping the classic Hollywood vibe, the film will be shot in black and white.
The film has been written by Fincher's father Jack Fincher and produced by Cean Chaffin.
Mankiewicz was a reporter and a critic in the 1920s. He was recruited by Paramount to work in the movie business in the late 20s.
Mankiewicz worked on many classic films such as 'The Wizard of Oz' (1939), 'Pride of the Yankees' (1942), 'Gentlemen Prefer Blondes' (1953), and 'Citizen Kane'.
'Mank' will be Fincher's first movie since 2014's Gone Girl.