How many movies have Mitchel Musso and Richard O'Brien acted in together?

They have worked on 3 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 Perry Files - Animal Agents (2013). They have not worked together since Phineas and Ferb The Movie: Candace Against the Universe (2020). They are most known for their animation films together.