The members of Spinal Tap are reuniting -- but unplugging.

Christopher Guest, Harry Shearer, and Michael McKean, along with Second City alumnus Eugene Levy, are collaborating on a new comedy that moves away from the heavy-metal antics of Spinal Tap and into the world of folk music.

The Hollywood Reporter said the project is being written by Guest and Levy, who last collaborated on the dog-world mockumentary "Best In Show."

"It deals with three folk acts that get together for a memorial concert at Carnegie Hall because a famous legendary folk manager has died," Guest told The Hollywood Reporter.

"These acts were active in the '60s but have been out of the business since the early '70s. They must now travel to New York to honour this man who has died, and play the concert."

Longtime fans of Guest, Shearer, and McKean will note the project echoes a one-off skit the trio performed on "Saturday Night Live" several years ago: a short documentary on a Peter, Paul & Mary-like traditional folk trio attempting a reunion.

The report said Guest, Shearer, McKean, and Levy will write new songs for the project, and many of the ensemble of supporting players who appeared in "Best In Show" will have roles in the as-yet-untitled folk comedy project.

Meanwhile, fans of Guest will get an taste of his work this weekend, when a new ad he directed for the Dockers clothing line airs during Sunday's Super Bowl.

The ad, which makes use of "Guest's signature ad-lib style and a talented cast of improvisational actors," takes place "in a country club setting where all the men are conspicuously dressed in attire that usually serves as a trusty wardrobe stand-by for women," Dockers' parent company, Levi Strauss, said in a press release.

The 30-second clip will debut during the second quarter of the football game.