Knall and Fall as Imposters (German: Knall und Fall als Hochstapler) is a 1952 Austrian-German comedy film directed by Ulrich Bettac and Hubert Marischka and starring Hans Richter, Rudolf Carl and Curd Jürgens. It was followed by a 1953 sequel Knall and Fall as Detectives. It was shot at the Sievering Studios in Vienna and on location across the city. The film's sets were designed by the art director Fritz Jüptner-Jonstorff.
Two rural men are picked at random for parts in a film production in which they are to play a millionaire and his chauffeur. After an accident while shooting a scene, the car they are in runs out of control and ends up crashing into a sanatorium. The director, believing that a real millionaire has arrived at the financially struggling establishment, puts them up. They are forced for a while to live as imposters until matters are eventually resolved.