In 1923, Valentin appeared in a half-hour, slapstick film entitled Mysteries of a Barbershop (Mysterien eines Friseursalons).
The film script was written by Bertolt Brecht, directed by Erich Engel, and also featured Valentin's cabaret partner, Liesl Karlstadt, as well as an ensemble of stage, film, and cabaret performers, including Max Schreck, Erwin Faber, Josef Eichheim, and Blandine Ebinger. Although the film was not immediately released after it was completed in February 1923, it has come to be recognized as one of the one hundred most important films in the history of German filmmaking.