How many movies have Mammootty and P.K. Joseph collaborated on?

They have worked on 4 movies together! Their first movie together was Oothikachiya Ponnu (1981) while their highest rated movie together was Oru Mukham Pala Mukham (1983). They have not worked together since Oru Mukham Pala Mukham (1983). They are most known for their drama films together.