Lily Collins, Charles Dance, Tuppence Middleton, Arliss Howard, Ferdinand Kingsley, Jamie McShane, Joseph Cross, Sam Troughton, Toby Leonard Moore, Tom Burke, and Tom Pelphrey will also appear in the film.
“Mank” is based on a script by Fincher’s late father, Jack, who penned it prior to his death in 2003.
Specific plot details are vague, but sources say the story will follow Mankiewicz’s tumultuous development of the script for “Citizen Kane” — which would go on to be considered one of the best films of all time — alongside director Orson Welles. Despite the “Citizen Kane’s” critical success, the script was the only part of the film to win an Oscar.
The film will also be shot in black and white, with production scheduled to begin in November.
Fincher will produce alongside producing partner Cean Chaffin and Douglas Urbanski.
“Mank” marks Fincher’s first feature since Fox’s “Gone Girl” starring Ben Affleck and Rosamund Pike. Fincher has primarily worked in television since “Gone Girl,” partnering with Netflix to direct shows such as “House of Cards,” “Mindhunter” and “Love, Death & Robots.”
Seyfried was most recently seen in Fox’s “The Art of Racing in the Rain” alongside Milo Ventimiglia. She also recently reprised her role from 2008’s “Mamma Mia!” film adaptation in “Mamma Mia! Here We Go Again” last year. She is repped by Innovative Artists.