Surprising Facts About This Is Spinal Tap— The OG Mockumentary

Improv Wizards

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This Is Spinal Tap was so heavily improvised that the three main actors were given writing credits for the movie. The idea for the movie itself was born out of an improvised sketch that Guest, Shearer, McKean, and Reiner worked on together for a 1978 sketch show called The TV Show.

Virtually all the dialogue in the film is improvised. The actors were given outlines for each scene and some basic information, but no actual script. As often as possible, Reiner used the first take of each scene in the final cut of the film to capture the actors’ first reactions.