How many movies have Martin Olson and Robert Hughes collaborated on?

They have worked on 4 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: The O.W.C.A. Files (2015). They have not worked together since Phineas and Ferb: The O.W.C.A. Files (2015). They are most known for their tv movie films together.