Is Spinal Tap a Real Band?

My heroes, Spinal Tap, will be on The Daily Show tonight in support of their new album.

Philosophers of language have long grappled with the question of fictional names. What does "Hamlet" mean given that there is no Hamlet for the word to refer to? This case seems an interesting twist on this question. when there was just the movie, This Is Spinal Tap, it could be said pretty straightforwardly that there was no band, Spinal Tap, but a collection of comedians acting as if there was. They played gigs after that, for example, in 2007 at the Live Earth benefit, they played "Big Bottom" with the most bass players to ever simultaneous play: Nate Mendelof the Foo Fighters, Robert Trujillo, Kirk Hammett, and James Hetfield of Metallica, Gordon Moakes from Bloc Party, and the Beastie Boys' MCA. This clearly could be called a comedy routine, a live performance of the fictional group from the film.

Other performers use stage names. Robert Zimmerman isn't playing Bob Dylan, he is Bob Dylan. But this seems different from the case of Spinal Tap.

At the same time, the Blues Brothers did seem to make the move. In opening for the Grateful Dead at the closing of Winterland in 1978, they were a band, they performed for the sake of the music and not the laughs. Is that the defining property, is it in the head? But what about Spinal Tap? There is always that comic edge to them, but if we put it in the head, can we know?

So, is Spinal Tap a real band?