How many movies have B.B. Bhalla and Prakash Mehra collaborated on?

They have worked on 2 movies together! Their first movie together was Haseena Maan Jaayegi (1968) while their highest rated movie together was Ek Kunwari Ek Kunwara (1973). They have not worked together since Ek Kunwari Ek Kunwara (1973).