Matthias Schweighöfer (German: [maˈtiːasˈʃvaɪkˌhøːfɐ]; born 11 March 1981) is a German actor and filmmaker known for his work in several German and American film productions. He appeared as Lieutenant Franz Herber in the 2008 film Valkyrie. In 2021, Schweighöfer appeared in the Netflix film Army of the Dead, directed by Zack Snyder, as Ludwig Dieter. He reprised his role in the prequel film, Army of Thieves, which he also directed. In 2023, he appeared as German theoretical physicist Werner Heisenberg in Christopher Nolan's biographical thriller  Oppenheimer, about J. Robert Oppenheimer and the development of the atomic bomb during World War II.