How many movies have Mike Diederich and Thomas Brodie-Sangster collaborated on?

They have worked on 2 movies together! Their first movie together was Phineas and Ferb The Movie: Across the 2nd Dimension (2011) while their highest rated movie together was Phineas and Ferb: Star Wars (2014). They have not worked together since Phineas and Ferb: Star Wars (2014).