NEW YORK • Cameron Mackintosh is sitting in his office in the theatre district, heaping Mackintoshian enthusiasm on the casting coup he thinks he has scored for the new revival of Miss Saigon, which officially opens on Thursday and is the latest of his 1980s and 1990s megahits to return to Times Square.

The major discovery the first time around for Miss Saigon was Lea Salonga.

He is certain that his new Kim, American actress Eva Noblezada, is another teenage sensation.

He says: "You just know that they have some innate stillness in them that makes you go, 'They need to be up there'."

Audiences know, too, that with his list of hits on both sides of the Atlantic - among them Cats, Les Miserables and the longest- running Broadway musical ever, The Phantom Of The Opera - Mackintosh, 70, is one of the most successful producers of all time.

But it is also clear, as he prepares to accept an award tonight from Signature Theatre in Arlington, Virginia (the company's Sondheim Award, named for the revered composer-lyricist and bestowed annually on a figure chosen in consultation with Stephen Sondheim himself) that the era in which he reigned supreme is drawing to a close.

The megamusical is not yet down for the count: Phantom, which has been at New York's Majestic Theatre since 1988, has passed the 12,000th-performance mark and Les Miserables has been to Broadway thrice since 1987 under Mackintosh's auspices.

A new Les Miserables company goes out on the US circuit in autumn and a new Miss Saigon the next year.

Mackintosh's sometime partner, Andrew Lloyd Webber, also has four shows on Broadway so it would be hard to argue for the irrelevance of British theatre royalty.

Still, Mackintosh is enough of a student of theatre trends to understand that he is not in the vanguard anymore. "This particular cycle is over," he said in 2014. "What it needs is a new Cameron Mackintosh to come up and work with a younger generation."

The kind of spectacle of which he has been the champion - musical epics framed by war and love, stories featuring flying chandeliers, helicopters and nannies - is no longer the artistic vogue.

The only thing flying at Hamilton is money into the box office.

The new musicals making a mark this season on Broadway - Dear Evan Hansen; Natasha, Pierre And The Great Comet Of 1812; and Come From Away - are quirkier pieces, by a mostly younger cadre of composers, book writers and lyricists, whose ideas for the form are driven more by the dictates of intimacy and new musical styles than by pyrotechnics.

Miss Saigon's initial Broadway run (4,092 performances, 1991- 2001) was spectacular by any other measure than a Mackintosh yardstick.

The subject of the Vietnam War had narrowed the family-viewing pool somewhat. This is partly why the new run is being advertised as "limited" through January next year.

But if it catches fire, who knows?

Mackintosh waxes poetic about the actors he has found who are making their Broadway debuts, such as Jon Jon Briones, playing the bravura role of the shady Engineer, originated on Broadway by the Tony-winning Jonathan Pryce.

The story, he says, has never been more relevant, telling of a young Vietnamese woman who falls in love with an American G.I. and is left behind with their child after the fall of Saigon.

"The sad truth is that the world has caught up with Miss Saigon. You've got the refugees - they're climbing over the walls," he says, referring to the famous scene re-created in the musical, when the gates of the American Embassy closed, shutting out the Vietnamese desperate for a spot on one of the evacuation helicopters.

The discussion reminds him of how contemporary politics plays into his hands, even in a piece depicting earlier history, such as Les Miserables, with its depiction of the barricades during the Paris uprising of 1832.

"What's going to happen when we do it in Mexico?" he asks. "I think I just have to raise the Mexican flag during One Day More and the audience will give it a standing ovation. I have to send a thank-you to The Donald, for making all my shows so current."

But back to Miss Saigon - the helicopter that swooped out of the rafters so famously in the original? Is it back?

A laugh erupts from his gut.

"Bigger," he says. "And better than ever."

WASHINGTON POST