How many movies have Ken Duken and Tom Zickler collaborated on?

They have worked on 3 movies together! Their first movie together was 1½ Knights - In Search of the Ravishing Princess Herzelinde (2008) while their highest rated movie together was Conni & Co 2 - Das Geheimnis des T-Rex (2017). They have not worked together since Dream Factory (2019). They are most known for their comedy films together.