How many movies have Peter Sellers and Stuart Freeborn collaborated on?

They have worked on 6 movies together! Their first movie together was The Mouse That Roared (1959) while their highest rated movie together was Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb (1964). They have not worked together since The Optimists of Nine Elms (1973). They are most known for their comedy films together.