This Is Spinal Tap is a 1984 American mockumentary comedy film co-written and directed by Rob Reiner in his feature directorial debut. The film's starring trio, who also co-wrote the film, are Christopher Guest, Michael McKean and Harry Shearer. Guest, McKean and Shearer play members of the fictional heavy metal band Spinal Tap, which is characterized as "one of England's loudest bands". Reiner plays Martin "Marty" Di Bergi, a documentary filmmaker who follows them on their American tour. The film satirizes the behavior and musical pretensions of rock bands and the perceived hagiographic tendencies of rock documentaries such as The Song Remains the Same (1976) and The Last Waltz (1978), and follows the similar All You Need Is Cash (1978) by the Rutles. Most of its dialogue was improvised and dozens of hours were filmed.