How many movies have Donna Williams and Helen Steinway Bailey collaborated on?

They have worked on 7 movies together! Their first movie together was Harry Potter and the Half-Blood Prince (2009) while their highest rated movie together was Harry Potter and the Deathly Hallows: Part 2 (2011). They have not worked together since The Huntsman: Winter's War (2016). They are most known for their adventure films together.