(L to R): Emily Padgett as Daisy Hilton and Erin Davie as Violet Hilton in “Side Show” at the Kennedy Center. (Joan Marcus/Joan Marcus)

Erin Davie and Emily Padgett remember the first time they saw themselves in costume for “Side Show.” After hours and hours of joint fittings with costume designer Paul Tazewell, they were finally wearing the identical drapey, drop-waist dresses created for the musical’s opening scene. They knew this moment was coming, but they still weren’t prepared to open their eyes—with brown-eyed Emily starring through blue contacts — and see conjoined identical twins.

“We were very pleased with the results,” Davie recalled. “We weren’t sure how it would work until we got everything on — makeup, hair, costumes. And then we did, and it was really creepy. We were like, ‘Wow. This really works.’ We took a lot of pictures that day.”

That day was last fall, when Davie and Padgett were in rehearsals at California’s La Jolla Playhouse, the Kennedy Center’s producing partner for “Side Show.” Here in Washington, the musical about real-life conjoined twins Daisy and Violet Hilton, stars of the Vaudeville circuit in the 1930s, runs through July 13.

For the actresses, performing at the Kennedy Center continues an adventure that began more than a year ago, when they showed up at a New York audition with — as the casting call instructed — a big bag of shoes with varying heel heights. Davie and Padgett have both held a smattering a Broadway roles, so they knew of each other but had never met. At the audition Davie, who is 5-foot-7, wore flats, and Padgett, who is 5-foot-6, wore heels. A casting director paired them like partners in a dance class. They found out they got the parts the next day, and they’ve been stuck together ever since.

“There is no other experience like this, where from the audition process on, I was going in with someone else, and I had to match her,” Davie said.

Costume design sketch of the Hilton twins in tulle capes in SIDE SHOW by Paul Tazewell. PICTURED: These are the dress suits the twins wear for the wedding at the Texas Centennial. It is when within their story that Violet is getting married to Buddy. (Courtesy of Paul Tazewell /Kennedy Center)

For the first two weeks of rehearsal, the actresses voluntarily agreed to lace themselves into a custom-made corset and learn the show while completely connected. “We had to decide things like, ‘Where are we going to put our water bottles?’ and ‘What are we going to do on break?’ and ‘Who has to go the bathroom?’ ” Padgett recalled.

But they knew all along that the corset wasn’t going to work onstage — costume changes were simply too complicated. In the original 1997 Broadway production of “Side Show,” the actresses portraying Daisy and Violet simply stood close together. But in this production, with major revisions and new songs, director Bill Condon wanted to better simulate the four-to-six-inch “fleshy link” that stretched like an accordion and connected the Hilton sisters at the back of their hips.

“They decided early on that they wanted us actually, physically stuck together in some form, because it shows. The physicality shows,” Davie said. “There is no tension if there’s nothing actually holding us together.”

So Tazewell started experimenting. In the end, three mechanisms have been used to “conjoin” Davie and Padgett. In the opening scene of Act 1, loose-fitting dresses are sewn together. For the opening scene of Act 2, a song-and-dance number called “Stuck on You,” they wear pantsuits connected with a circular zipper. One set of costumes has skirts that are so puffy, the actresses are not actually attached. But when wearing the remaining eight of 11 costumes designed for the show, the secret to making Davie and Padgett appear conjoined is magnetic attraction.

Powerful rare-earth magnets first turned up in theater costume designs about five years ago, Tazewell said. “It’s almost like a snap,” he said. But it’s a “snap” that cannot be used by performers with pacemakers or metal pins holding bones together. He has used them in other shows to do everything from holding hats on heads to dramatically detaching Chippendale suspenders. For “Side Show,” he wanted the twins’ costumes to capture the height of the vaudeville era. like a romanticized dreamscape of the 1930s, complete with stunning, sparkling floor-length evening gowns.

“For me, it became a question of, ‘If we are connecting [Davie and Padgett], how do we get the clothes on and off of their bodies?’ It seemed to me that it was going to be easier to do quick changes, and have the fit of the clothes be more precise, if they could change separately and then connect together with magnets.”

So he designed what he calls “magnetic girdles” – non-stretch canvas panels that each actress wraps around her waist before the show. “They’re comfortable,” Davie said. Her magnet is sewn into a pocket at her right hip; Padgett has one on her left. Each twin has a dresser who Davie said is “very busy throughout the whole show.” But they do the magnetic connection themselves, being extremely careful as they run toward the stage not to brush by any metal doors that the magnets could stick to. (That’s happened; it hurts.) Then, in the wings, they connect.

“It has become second nature to us,” Davie said. “We both pull our skirts down and taut so there are no wrinkles, so that they will attach at the exact same spot and it feels right, and then we let them click together. This happens within seconds. And it’s usually a go.”

It took a bit of trial and error, Tazewell said, to find magnets strong enough to maintain a connection through various fabrics but not so powerful that the actresses couldn’t disconnect.

But “conjoining” Davie and Padgett was only half the job. Tazewell and wig designer Charles G. LaPointe also had to convince the audience that they look twins. “Erin and I are very similar, physically, but we are different women,” Padgett said. Their bodily distinctions include Davie’s longer neck and Padgett’s bigger breasts. Tazewell used strategic padding to create the illusion that the actresses’ have identical body types, and for the Kennedy Center run, had lifts added to Padgett’s shoes.

“We started to get very specific and picky about everything,” Davie said. “We wondered, ‘What can we do get this even more perfect?’”

“It’s magical,” Padgett added. “We really do look like sisters — and twins.”

Ritzel is a freelance writer