Jojo Rabbit will follow a young German boy in Hitler's army who finds out that his mother, played by Johansson, is hiding a Jewish girl inside their home.
Rockwell will appear in the film as a Nazi captain who runs a Hitler Youth camp, noted The Hollywood Reporter. Waititi, who recently helmed Marvel's Thor: Ragnarok, will also be starring as Adolph Hitler who is the boy's imaginary friend.
Waititi, who has also directed Hunt for the Wilderpeople and What We Do in the Shadows, wrote the script for Jojo Rabbit and is producing alongside Carthew Neal and Chelsea Winstanley. Production on the film is expected to start in the spring, Variety reported.
Rockwell, who was last seen in Three Billboards Outside Ebbing which earned him the Oscar for Best Supporting Actor, will also star as President George W. Bush in Adam McKay's untitled biopic about former Vice President Dick Cheney starring Christian Bale.