the famous lilies scene, the songwriter actually did the singing. poitier was considered a bankable star in 1967, starring in a landmark film "to sir with love". >> those kids are devils incarnate. i tried everything. >> reporter: playing characters that would force audiences to confront racial prejudices. >> they call me mr. tibs. >> reporter: he would also challenge the hollywood establishment, forcing a change in his iconic role as detective virgil tibs in the 1967 academy award winning "in the heat of the night" because of a scene that would require him to acquiesce to a racist character. >> i'm going to take you over to brownsville and put you on the bus myself. >> you aren't taking me anywhere, you dig? you're holding the wrong man! >> reporter: that same year he would star in the water shed film "guess who's coming to dinner," alongside spencer tracy and katharine hepburn. >> mom, this is john.