How many movies have Oskar Haarbrandt and Willy Mattes collaborated on?

They have worked on 2 movies together! Their first movie together was Der Verteidiger hat das Wort (1944) while their highest rated movie together was Liebe verboten – Heiraten erlaubt (1959). They have not worked together since Liebe verboten – Heiraten erlaubt (1959).