The Sound Of Music Children: After They Were Famous Since its release in 1965, The Sound Of Music has been seen by more than one billion people worldwide, making it the most popular film ever. The Oscar-winning movie took nine months to film and during that time the seven young actors who played the von Trapp children forged a unique friendship that lasts to this day. In this one-hour special, they return to Salzburg for the first time since then to relive the experience. With unseen footage of the making of the film and home movies shot by their mothers, the recollections of the actors are surprisingly poignant, harking back to a lost time of innocence and anticipation.