After deciding on the tone of the film, Mills needed to find suitable actors to play the father and son in the film, and then thought of Ewan McGregor and the old actor Christopher Plummer. So he wrote an email to the two actors and invited them to star in the movie. In the invitation letter to Ewan McGregor and Christopher Plummer, Mills told the story and details of the film in detail, as well as his understanding and cognition of the two characters. These two letters touched the two actors, especially Christopher Plummer . He even felt that this was the role he created for him. And Plummer , who was in his 80s, had empathetic love and recognition for this role.
Ewan McGregor came to play his son Oliver is a very early idea Mills, before the completion of the script, Mills hoped that Ivan could play this role. Mills felt that Ivan’s temperament was similar to Mills, but his British accent would be an obstacle to the film, so Ivan asked Mills to read the script aloud to him so that he could learn an authentic American accent.
