LEFT TO RIGHT: Harry Shearer, Christopher Guest and Michael McKean in 1984's This Is Spinal Tap
Everett Collection

Grossing only $5 million in its initial limited box-office run 30 years ago this month, This Is Spinal Tap has nevertheless cranked up its reputation as one of the funniest films ever made. A mockumentary following “the world’s loudest band,” Spinal Tap is eminently quotable and gut-splittingly hilarious. In fact, the movie was named in 2002 to the U.S. National Film Registry, which preserves films deemed “culturally, historically or aesthetically significant.” Not bad for a picture featuring the hit song “Big Bottom.” On the film’s 30th anniversary, co-creator and star Christopher Guest reflects on how it was almost never made.

“Michael [McKean], Harry [Shearer], Rob [Reiner] and I had this idea of doing a comedy about a rock band and were given money to write a script by a production company on the verge of going under. We sat there for a few days of writing and realized this would never work if we actually wrote it; we had to improvise it and do it in the form of a documentary. So we took the money they gave us and got into character and just started shooting stuff and made a rough, but funny, 20-minute reel of what the movie was going to be. And then the studio that hired us to write the movie went out of business. Instead of letting it die, we went around Hollywood showing our little movie, trying to get somebody to give us the money to finish it, and we were met with a resounding, ‘We don’t get this. What the hell are you doing?’ They didn’t know if it was real or not. They thought maybe it was a real documentary about idiots. Eventually, [TV producer] Norman Lear said, ‘Yes, let’s make this movie.’ Without Norman, the movie wouldn’t exist, and no one would ever have heard ‘Big Bottom.’ ”