‘The Gilded Age’ HBO: Bertha’s ‘gasp’-worthy gown, explained

The following contains spoilers from the Season 1 finale of “The Gilded Age.”

“I’m worried that it may be too small,” says Bertha Russell, the socially ambitious wife of a railroad tycoon at the center of HBO’s “The Gilded Age.” “New money” incarnate, Mrs. Russell (Carrie Coon) is talking to her staff about the opulent ball she’s hosting to christen her Fifth Avenue estate and, she hopes, reach New York society’s inner circle. Will the city’s notables attend the extravagant event? And — more important — what will she wear?

These questions are answered in Monday’s season finale: With a bit of strategic intimidation, Bertha secures the attendance of Mrs. Astor (Donna Murphy) and, by extension, the rest of the hard-to-please elite — including her elusive neighbors, Agnes Van Rhijn (Christine Baranski) and Ada Brook (Cynthia Nixon).

Bertha hosts the affair in a show-stopping black-and-white ball gown, decorated with leaf-shaped appliqués and lined with a whimsical periwinkle chiffon. (All paired with jewels that echo the railroad empire built by her dashing husband, played by Morgan Spector.)

The fit is edgy for both its highly graphic nature and for what’s under her corresponding cape: asymmetrical sleeves, the left of which is voluminous in shape, while the right is a single sliver of fabric.

“There was a long, heated debate in my fitting about whether or not she could get away with that tiny sleeve without a scandal,” recalls Coon. “At the time, it was incredibly inappropriate for a woman to have a sleeveless gown, because that would [mean] you were a courtesan, a prostitute. I was advocating for some woman to come into the ball and gasp when they saw my bare arm! It was breathtaking. I loved it.”

The fact that most of Bertha’s attire this season has been much more vibrant in color makes her last look all the more meaningful.

“Bertha is discovering this language of glamour and what it looks like in this new world that her husband is creating, and since she has an unlimited amount of money, there’s an adventure and a boldness within her style, and a more immediate embrace of new ideas,” says costume designer Kasia Walicka-Maimone. “But she also desperately wants to become part of this society of women, and she is probably trying to impress them more than vice versa.”

For the ball, “I went for these super light colors so that Bertha fits within the aesthetics of the ball, because the idea was that she is finally part of the world that she’s been trying to break into,” Walicka-Maimone adds. “Nevertheless, the black appliqué still draws attention and makes her stand apart from everybody else.”

“There’s an adventure and a boldness within her style, and a more immediate embrace of new ideas,” says costume designer Kasia Walicka-Maimone of Bertha Russell (Carrie Coon).

(Alison Cohen Rosa / HBO)

A mere sampling of the season’s 5,000-plus costumes, Bertha’s gowns were usually adorned with glistening beaded fringe, billowing feather arrangements and hats so tall that the top of the carriage had to be removed in order for Coon to not need to tilt her head sideways. Such embellishments not only illustrated the period’s opulence — “The amount of money they spent on their dresses was endless, so we had to find tricks to show that without actually spending that kind of money on each outfit,” says Walicka-Maimone — but also drew the audience’s eye away from Coon’s pregnancy.

“I was already showing, so my waist is about six inches too high, and they added more volume to make sure they could conceal my pregnancy as much as they possibly could,” says Coon with a laugh. “Whenever you see Bertha in a fancy cape, you can rest assured that it was shot in the last two weeks of filming. It was kind of a wild thing for costumes to have to figure out where to put my boobs, as they kept getting bigger!”

There was an added benefit of Coon’s pregnancy too: “Because I was wearing tennis shoes and no corset, I was the most comfortable woman on set,” she says. “So there’s almost something about the looks that relaxes in a way, that makes me think of a woman who’s found her voice, who is in her power and strength. And her looks almost settle down into something that’s very emblematic of her.”

Since capturing the bash required a lengthy shoot with an ensemble of dancers, the cast killed time by showing off their outfits for each other with an impromptu fashion show.

“It was magnificent when everyone came out of their dressing room to see what everyone was wearing, like going to an actual ball,” Coon recalls. “We had had kind of a wacky night, so by the time the actors actually went onto the ballroom floor, people just kept laughing hysterically and bumping into everyone. We didn’t shoot that very long, and I really can’t believe they got a usable take because it just felt like chaos.”

The Russells — played by Morgan Spector and Carrie Coon — in “The Gilded Age.”

(Alison Cohen Rosa / HBO)

Walicka-Maimone is currently preparing costumes for Season 2 and promises that the series is just getting started: “Since Season 1 was such a giant learning process on how to make this enormous show, now we know it and can really play.” For her part, Coon hopes Bertha’s unapologetic luxury has been an entertaining escape for viewers at this time.

“There’s nothing wrong with something that is aesthetically beautiful, to look at just in this moment,” she says. “We all need those hours away from the chaos that is the world we’re living in right now.”