How many movies have Karsten Willutzki and Petra Kilian collaborated on?

They have worked on 4 movies together! Their first movie together was Einfache Leute (2007) while their highest rated movie together was A Night at the Grand Hotel (2008). They have not worked together since Mein Sohn, der Klugscheißer (2016). They are most known for their tv movie films together.