Christopher Haden-Guest, 5th Baron Haden-Guest, known professionally as Christopher Guest, is a British-American actor, comedian, screenwriter and director. Guest has written, directed, and starred in his series of comedy films shot in mockumentary style. The series of films began with This Is Spinal Tap and continued with Waiting for Guffman, Best in Show, A Mighty Wind, For Your Consideration, and Mascots.

This Is Spinal Tap is a 1984 American mockumentary film co-written and directed by Rob Reiner. The film stars Christopher Guest, Michael McKean and Harry Shearer as members of the heavy metal band Spinal Tap, who are 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.