How many movies have Costas Ferris and Kostas Vrettos collaborated on?

They have worked on 2 movies together! Their first movie together was Prometheus Second Person, Singular (1975) while their highest rated movie together was Δυο Φεγγάρια τον Αύγουστο (1978). They have not worked together since Δυο Φεγγάρια τον Αύγουστο (1978).