Really, the only amazing thing about a Xanadu musical is how long it took to happen.

Xanadu, the notorious 1980 movie-musical starring Olivia Newton John (pictured), is coming to the Broadway stage. In doing so, it will raise camp levels in New York — already well above the national average — to roughly a billion parts per billion, a peak unseen since Carrie the Musical padded into the wings, leaving abashed little pig’s-blood footprints behind it.

A friend of a friend gifted me this: “The cast of [Boy George-penned, Rosie O’Donnell-produced flop] Taboo x performing Carrie = Xanadu. Just add roller skates.” Yes, skates! That’s the whole point of the movie: A Greek muse helps a young schmuck open a roller disco. Kind of a timeless story, really, if you’re one of those select creationists who claim time began in 1974 and ended in 1979.

In case you’re wondering, yes, they’ll be using all the original music from the film. The book is by the distressingly legitimate playwright Douglas Carter Beane (“As Bees in Honey Drown”). But this is really the only drawback I can see on the horizon. The stage is set for spangly disaster.

How much camp is too much camp? Can irony perform so many contortions, it goes from camp to cramp? Can I now make the semiotic leap from “cramp” to “crap”? (No.) Has anyone whispered the words Starlight Express to the producers yet?

addCredit(“Xanadu: Everett Collection”)