How many movies have Hayden Collow and Philippa Boyens collaborated on?

They have worked on 9 movies together! Their first movie together was The Lord of the Rings: The Two Towers (2002) while their highest rated movie together was The Lord of the Rings: The Return of the King (2003). They have not worked together since Mortal Engines (2018). They are most known for their adventure films together.