The screwball comedy, getting its UK premiere this week at Glasgow's Tron Theatre, is half set in a fictional 1940s small-town Texas and half in the real-life court of Ludwig II of Bavaria. This 19th-century monarch had a love of Wagnerian opera, an alleged taste for naked midnight picnics and a penchant for building fairytale castles. The most famous of these, Neuschwanstein, was so over the top that it gave the designers of Disneyland in California the inspiration for their Sleeping Beauty castle.
Such lavish building sent the king perilously into debt and some believe the political fallout led to his suspiciously speedy death. But without Ludwig there would be no theatre and annual festival dedicated to Richard Wagner in the town of Bayreuth. Indeed, without the king's patronage, the composer is unlikely ever to have completed his Ring Cycle.
Whether or not the king was actually mentally ill - as his opponents alleged - or merely an eccentric in the high-spending mould of Michael Jackson, Rudnick uses his story to explore the relationship between beauty and madness.
The writer, whose Hollywood credits include Addams Family Values, In And Out and The Stepford Wives, tells two stories at once, comparing Ludwig to fictional Texas teenager James Avery who has a similarly operatic fantasy life. In parallel coming-of-age tales, the playwright shows the two young men falling in love with swans - one real, one crystal - both discovering their homosexuality and both seeking an escape from the mundane details of life in their pursuit of beautiful things.
"I just thought Valhalla! was a great title," says director Andy Arnold, who stumbled across the play almost by accident. "I got hold of the script and thought it was the most hilarious play I'd ever read. It was wonderful. Even on the page, it leapt out at me. It's very cleverly written and, theatrically, a crazy play. It's almost like staging a pantomime, except the humour is more subtle; it's very dry, sharp and witty."
In an inspired piece of casting, Arnold has signed up Johnny McKnight to play the Bavarian prince, opposite the equally talented Mark Prendergast as James, in a high- calibre company of comedic actors. McKnight, renowned for his hilarious Little Johnny shows, is also a formidable panto dame, which should give him an appropriately flamboyant grounding for Rudnick's camp comedy.
"They're actors who know about that style of theatre," says Arnold, who gave McKnight his first job when he was not long out of college. "Johnny has got a style of performance that fits very well with the character he's playing. As soon as he read the script, he was desperate to do it and thought this part was made for him. There are Texan characters too, but there's definitely a bit of Glasgow patter in amongst it.
It shoes in very well to a Glasgow style of humour."
Add a set of rococo costumes by Kenny Miller and the show promises to capture the farcical spirit of Up Pompeii. That there is an in-house production at all in July might surprise some people, however. After all, the summer months are traditionally quiet for theatre in Glasgow (Edinburgh compensates with the Festival in August) and you could believe audiences were not interested in coming indoors at this time of year. But Arnold, who has upped the Tron's year-round output, has had the opposite experience.
"Before I arrived here there was no theatre really in July," says the director, who joined the Tron from the nearby Arches in 2008. "In my early days at the Arches, Michael Boyd invited us to bring over a few shows in July. We brought comedies, Sean O'Casey things, and they did very well. It was a different sort of audience, more of a tourist audience. So last year we did Cooking With Elvis (by Billy Elliot writer Lee Hall) and the whole thing was completely sold out - probably our best-selling Tron production. The trades holiday doesn't have the same impact any more and there are a lot of people visiting Glasgow. It's good to put on a play that is fun; entertainment being a key element."
Making that entertainment work can be a hard, if enjoyable, job. "It's a very fast-moving piece," he says. "One minute you're in Texas, then there are parachutes landing on the battlefields of Germany, then you're back in a gym again. I had to do a lot of preparation in terms of working out the staging, but when you've got a strong team of actors who are immediately in tune with the style of it, as well as bringing their own humour, it means even the first read-through was hilarious and it's a joy to work on."
Valhalla! is at the Tron Theatre, Glasgow, from Tuesday until 24 July
This article was first published in Scotland on Sunday July 4, 2010.