A few days after wrapping production, writer-director Werner Herzog’s film Bucking Fastard has announced Orlando Bloom and Domhnall Gleeson as its new cast members. Deadline was the first publication to report the casting-related news. As reported earlier, real-life siblings Kate and Rooney Mara portray inseparable twins Jean and Joan Holbrooke in the film, which marks Werner Herzog's directorial comeback after 2022's documentary Theater of Thought. It follows Jean and Joan, "who are so close to each other that they speak in unison, love the same man, and have the same dreams. They even make the same slip of tongue in unison. In search of an imaginary land, the Orkneys – where true love is possible – they start digging a tunnel through an entire mountain range."

Most popular for playing Legolas in the The Lord of the Rings franchise, Bloom stars in Bucking Fastard as the sisters' former romantic partner Gareth Mulroney. On the other hand, Gleeson plays a social worker from the government who helps the siblings get accustomed to life in the modern world after they turn into tabloid sensations.

The film reunites Herzog with his Bad Lieutenant cinematographer Peter Zeitlinger, The Fire Within: A Requiem for Katia and Maurice editor Marco Capalbo, and Rescue Dawn composer Ernst Reijseger.