A behind-the-scenes look at 19th-century opera

Sometimes, the opera that unfolds backstage is at least as colorful as the one playing out at the footlights. And in Terrence McNally's new play,

Golden Age

, at the Philadelphia Theatre Company, it's just as intense.

Golden Age, one of three world premieres that opened in Center City on Wednesday - the other two being at the Walnut main stage and InterAct - is the third of McNally's plays involving opera, and it's set at yet another world premiere. The smoothly performed production, directed by Austin Pendleton, continues the company's long association with McNally, whose Master Class premiered here and went on to win the best-play Tony.

Golden Age takes us to Paris, on a January night in 1835 when a rarefied audience attends the world premiere of Vincenzo Bellini's opera I Puritani. It's being delivered by four of the world's greatest singers at the Theatre-Italien.

That's what's happening onstage in Paris. But the stage McNally creates is the real-life other side, on Santo Loquasto's workaday curtain-dripping set, complete with five chandeliers in backstage storage. There, Bellini (Jeffrey Carlson, aptly high-strung) and the four stars preen, pout, strut, brood, and generally pump one another up yet drive one another crazy.

We're in a world where everyone works at the extreme edge of monumental egos. And all in the name of art. Everyone McNally portrays on this night was real, save a young nameless page, and you can easily imagine the great fun he had conjuring their backstories.

He turns each character into a distinct type; these folks grew on me during Golden Age, and stayed with me afterward. But the play itself - which has the broad sweep of an opera and, at three hours, lasts about as long - is too much of a good thing.

It becomes overbearing before the lengthy first of three acts ends, with much talk about art as an ideal and artists as gods. It picks up considerably when two divas who despise each other from simple, transparent jealousy become meshed in the backstage machinations. And there's also a hint throughout of tragedy afoot.

Still, the character of Bellini, in particular, becomes tiresome: his very presence demands coddling by the singers surrounding him, his ego forbids a scintilla of generosity about a single colleague, his overwrought, fey style sets him apart as caricature, and his utter lack of confidence - Will they love me out there? - makes him pathetic. All extremes, again and again.

Golden Age bursts with operatic allusions, and McNally - whose love and knowledge of opera are givens - makes certain that we get it all by context. He also has his characters speaking in contemporary English, which makes the play seem current and allows us to know them easily.

The excellent cast boasts Broadway veterans - Marc Kudisch, Hoon Lee, and George Morfogen - plus Christopher Michael McFarland, Roe Hartrampf, and young Dante Mignucci. The two divas are Rebecca Brooksher and Amanda Mason Warren; each pumps her character with a singular style. Ryan Rumery's superb sound design lets us hear the opera onstage while the characters are offstage, with us.