Entertainment

Sister act onstage and off

Football has its bands of brothers: the Mannings, Barbers and Harbaughs. Broadway has a singular sister act: the Boggess girls.

For the 25th anniversary of “The Phantom of the Opera” on Broadway, Sierra Boggess, late of “The Little Mermaid,” has come aboard through March 2 as the Phantom’s beloved Christine Daaé. Accompanying her — down in the orchestra pit, on the cello — is her sister Summer.And to think: A third sister is giving oboe lessons in Afghanistan. Her name’s Allegra. Is it fair to assume their parents are flower children?

“That’s correct!” Summer laughs. They grew up in Denver, where their dad was born, and their mom left Illinois “to live the John Denver song, ‘Rocky Mountain High.’ ”

Adds Sierra: “Our dad makes guitars, so we grew up singing.” Kind of like the von Trapp family, only smaller and female.

In any event, they say, playing Broadway together is a dream.

Backstage at the Majestic Theatre the other day, the sisters — Sierra’s 30, Summer, 32 — have the easy rapport of, well, sisters who shared a bedroom. Growing up, they took lessons in everything — piano, chorale, flute, cello and ice-skating — but since they were two years apart, they say, there was never any sibling rivalry.

Enter “Phantom.” The touring company came to Denver, and their father surprised their mother with tickets. They brought home the cassette tape for the kids — “So we knew the soundtrack inside and out!” Summer says.

Flash-forward a decade or so to Sierra’s big break: playing Ariel in “The Little Mermaid.” Critics torpedoed the show, and to this day, Sierra hasn’t read a single review. “That was my Broadway debut, so I wanted to keep it as great as the experience I was having,” she says. And that experience was even better, when Summer joined the pit. For a while, they shared an apartment in Midtown.

“Mermaid” sank. Soon after, Sierra joined the “Phantom” cast in Las Vegas — for the Reader’s Digest version of the show.

“It was 95 minutes long, and if you’re playing any of the leads, you just don’t stop,” she says. “But we wore clothes! We did NOT do a tassel version of ‘Phantom!’ ”

In Vegas, Sierra met composer Andrew Lloyd Webber, with whom she has something in common: His brother Julian’s a cellist, too. Before Sierra knew it, she was in England, starring in the “Phantom” sequel “Love Never Dies,” which British bloggers dubbed “Paint Never Dries.” No matter: She became engaged to the Phantom, a half-Turkish actor named Tam Mutu. (“I’m a fan!” Summer says.) They co-starred in London’s “Les Miz” before Sierra was invited to Broadway for “Phantom’s” big 25th.

Meanwhile, Summer, whose freelancing took her all around Broadway, the Met and the David Letterman show, had a few months free. She asked the show’s cellists if she might sub for one of them while her sister played Christine. No problem!

The sisters are terrific together, says Hugh Panaro, who’s played the Phantom to more than a dozen of leading ladies. “I really think Sierra’s the perfect Christine. Beautiful, gifted, fearless!” he says. And “Summer always looks into my [dressing] room. ‘OK, throw my sister around,’ she said the last time. ‘Just don’t hurt her!’ ”

Does Summer give her sister any advice?

“I tell her, ‘Always make sure the cello can be heard.’ Kidding!” she says, as Sierra cracks up. “Actually, I do find I have to consciously forget I’m working with Sierra,” she adds. “ It’s very emotional.”

Her sister agrees. “We can’t see each other — we can only hear each other. But I’m so glad she’s there!”