This time, the international pop-opera duo has gone from Gallic to Gaelic to recreate a battle-royal donnybrook — The Pirate Queen (Ireland's Grace O'Malley) vs. The Virgin Queen (England's Elizabeth Tudor), fierce feminists four centuries ahead of their time.

There's a lot of Riverdancing around the ladies who launch ships from their respective coasts — the producers, after all, are Riverdance, Inc. (Moya Doherty and John McColgan of the production company Riverdream). Amid the pockets of precision Irish dancing, the story being sung-through is essentially a clash of these royal iron wills, sparked when a buccaneer's daughter leads Ireland in rebellion against English rule in the late 16th century (an act also ahead of its time).

This, of course, causes much stage commotion, traffic-directed by Frank Galati and Graciela Daniele, gorgeously outfitted by Martin Pakledinaz (who has made the most of a clearly generous costume budget) and imaginatively set-designed by Eugene Lee.

And through it all, surrounded and supported by hordes of male drones, are the two queen bees: Stephanie J. Block wearing the green, Linda Balgord flying the Union Jack. It's a good match. Both hail from a history of strong women: Block made her Broadway bow as Liza Minnelli in The Boy From Oz; Balgord arrived on Broadway as Grizabella in Cats.

Block proved on opening night that her strength wasn't just for show. The most pressing, stressful and suspenseful question of the evening was "Who will turn up in the title role tonight?" Block had bailed out after about a half-hour of the last critics performance April 4 (her standby, Kathy Voytko, seamlessly assumed the role between scenes without ever stopping the show); also, Block had missed the two previous performances. "It killed me," she admitted. "It. Killed. Me. But the stage manager [C. Randall White] put things in perspective for me when he said, 'I just want to let you know: We've done 98 shows. You've done 94 out of the 98. You're doing okay.' The bottom line is that it's live theatre. I would love to be a movie star where they say, 'Okay, go home. We'll just do your take three days from now.' But, with live theatre, what are you going to do?"

Before she threw in the towel Wednesday night, did she ask herself what would Liza do? "Yes, of course. And Liza, I'm telling you, would probably do it all. The beauty about Liza is she's Liza — so she can tell a story as Liza, she can stop singing and say, 'I don't want to sing this anymore,' and the audience would still scream and cheer. When you're playing another character, you're kind of a slave to that other character to serve it well."

The culprit was a viral infection that had insidiously snaked its way into the company and finally found the star. "When you live with a cast, they become like family," Block said. "If Mama gets sick, the baby's going to get sick, and the baby's going to give it to Daddy, and it keeps going around the family. Our family started getting sick about six weeks ago, and it was just untimely that it happened to get to Mama right when she's opening."

She was speaking from a place of personal triumph, having heroically made it through the opening-night performance, looking and sounding good while doing it — and now she was meeting the press in the Apollo Lobby of the labyrinthine Hilton Theatre. "There's always an awareness and a control that you want to have as a singer — and, unfortunately, that wasn't there for me tonight," she confessed, "but I put that aside and said, 'All I'm going to focus on is telling the story. I'm going to give my heart. I'm going to give my soul. If that means I'm going to talk some notes, then I'm going to talk some notes. If I can sustain the performance — it doesn't matter as long as I'm staying true to Grace and staying true to the storytelling — I think that I'm going to be able to reach the audience regardless."

Apparently, Elizabeth I only comes in the large economy size. Eight minutes of her in "Shakespeare in Love" won Judi Dench the Oscar, and five scenes of her here could get Balgord into the Tony running. Despite the brevity of the role, the character casts a quite a shadow over The Pirate Queen. "She's omnipresent for the Irish, hanging over their heads and threatening their lives — their lives as they know them," admitted the actress.

"Elizabeth is such a fascinating woman. From the time she was a very young woman, she knew that her life was at risk, and, even when she was on the throne, she never really felt safe in her life. But I love her determination and her power in spite of everything around her. It made her life very dangerous. Also, with the Elizabeth of The Pirate Queen, the writers let the audience see underneath all the outer glory of her — to see she was a lonely woman who was disappointed in love and knew that there was really no choice for [her]."

The biggest trick — or is it a challenge? — is to appear regal while in motion, maneuvering those elaborate costumes that Pakledinaz has lavished on her. "It's not easy," she conceded. "One dress is so large and has so much fabric I really can't even hold the handrails backstage so I just have to hike it up as much as I can and, basically, go sideways. I don't really fit going straight across. I can't get through doorways because the width of the farthingales. One is them is about six feet across. We have to do what we call 'the crab walk.'" Most of the male characters in this conscience-raised musical are committed to a block-that-Block agenda — Marcus Chait as her abusive first husband, Jeff McCarthy as her domineering dad and William Youmans as Elizabeth's cauldron-stirring statesman.

Then there is her true love, played by Hadley Fraser, a 26-year-old import from London's Les Miz (Marius, of course) making his Broadway debut. "It's a dream come true to be on 42nd Street and in the home of musical theatre," he trilled. "To be in a show of this magnitude and of this class is just wonderful for me. I'm pinching myself."

There are rewards being second fiddle to a firebrand feminist, and Fraser's come in the second act. "When Grace's ex-husband returns and I step in — that's when the drama is at its most stunning and complex and visceral. Then, shortly afterwards, I get a scene where I go and plead to change places with Grace in prison. It comes with a song I'll always love to sing."

Chait said he didn't do any special research into the life of Grace's battering, brutish ex. "I just got drunk a lot and beat up my wife." (Pause.) "I'm kidding." His wife is Melissa Bell of Thoroughly Modern Millie and Wicked. "We met doing Titanic on the road."

Like the rest of the cast, he wore the look of somebody who had just crossed an invisible finish line. "Tonight felt kinda surreal. You work toward something for so many months, hoping it goes well, and it always seems so far in the distance. Then, suddenly, you're up on stage and your friends and your family are out there, and you're, like, 'This is opening night on Broadway, and I'm in a Boublil and Schönberg piece. It's a fantastic feeling."

Schönberg's look of relief was tempered with a touch of exhaustion: "I'm tired. I'm very tired. I'm sick and tired — and relieved at the same time. We take nothing for granted so we'll see what happens. At least, at last, we have the show we wanted, and that's the important thing." It is a different show that what premiered in Chicago. "Every project is difficult. I don't know an easy project. Doesn't exist. When it's easy, it's not very good."

Boublil echoed the same sentiments. "I think really it was the show I dreamed it would be. It has been 12 weeks of exhausting — exhilarating, sometimes — work, all without much sleep. It was probably the most tiring 12 weeks of my life, rewriting 50 percent of the lyrics.

"I had to do a lot of work since Chicago, and I had some great help from Richard Maltby Jr., my old friend and collaborator with Miss Saigon. We loved being with each other and working together. It's going to be a hard split now, not seeing each other after tomorrow." The one new song in the show — "Woman," which, he said, "gives the backbone to the show that it needed from the beginning and that was sorely missing in Chicago — was actually written there, but too late to be put into the show. "We had to rewrite inside the songs," he said. "We'd rewrite a section here, a section there. One word would change a sentence, a sentence would change a scene, a scene would change the whole show."

Much of the problem, Maltby admitted, has to do with Americans' unfamiliarity with Irish lore. "It's a hunk of history we know nothing about. We know Tudoring, and we know Elizabeth. We don't know Ireland. We don't know clans, the royalty of clans and all that stuff. Funnily enough, it's better to see it a second time. When you come in a second time, knowing what you know the first time, the show makes a lot more sense.

"If you'd have seen it in Chicago, you would be quite amazed at the changes. The truth of the matter is: I don't know any show that has had a revision as substantial as this. In order just to give it action and focus, you had to rewrite just about everything except for the best set pieces. They're sorta anthems. Everything else that involved action had to be rewritten. It took us two years to write Miss Saigon. It took us two months to rewrite this."

The producers of The Pirate Queen had battened down the hatches earlier in the day and downsized their opening-night party to "a private party," meaning No Press Allowed. Interviews were done in a makeshift area at the theatre while others frolicked in the foyer rotunda, partaking of the chocolate-dipped strawberries and champagne.

In the opening-night crowd: Joan Allen, CBS "Early Show" anchor Hannah Storm, Patrick Wilson and his wife Dagmara, director Wes Craven and Fran Drescher.

There were a lot of friends of the court among the first-nighters. Ma Joad (Lois Smith) was there for Galati, her Tony-winning adapter and director of The Grapes of Wrath. Christiane Noll — who opens in The Witches of Eastwick down at Virginia's Signature in June ("I fly. I get to fly and levitate and everything") — was there for a husband in the ensemble (Jamie Laverdiere). Of course, Charlotte Moore and Ciarán O'Reilly of The Irish Rep were there — and there for a Riverdance hoofer, Padraic Moiles (he was a 10-year-old Sean O'Casey in their terrific production of Grandchild of Kings in 1992). And Gabriel Byrne was there for the producers: "I've known John for 25 years so they're old family friends. I really admire what they've done here. It takes an incredible amount of bravery to put on a Broadway musical."

And, as if the Hilton needed another Irish queen, producer Liz McCann (on the mend from a fall) made a grand entrance in her wheelthrone.