On Friday morning, just hours before designers Laura Kim and Fernando Garcia showed the Monse spring collection at New York Fashion Week, the scene inside their Tribeca studio was calm and quiet. Kim's South Korean mother arranged a breakfast platter in the kitchen while a small army of seamstresses and interns worked with laser focus behind a wall of clothing racks. Pinned on the wall was a meticulously messy mood board featuring stills from "The Grand Budapest Hotel," street style photos, and motifs found on vintage scarves. A candle flickered at the base of a healthy potted plant, despite the early hour — although on second thought, this was perhaps the only hint that no one had left the space since the day before.

The Monse team operated that day as though there was a sleeping child in the room — the child in this case being the collection, which Kim and Garcia were, in fact, working on all night. Garcia said he had about three hours sleep, although Kim protested later that that number was incorrect. "Okay, he had five!" she said with a laugh. "I was still there when he left. I had two. But I don't feel tired. I'm well-fed."

Despite their outward appearance, this has not been a quiet period for Kim, 34, and Garcia, 29, who first met almost a decade ago at the late Oscar de la Renta's, which they left in February of last year to open Monse. In three short seasons, the label has managed to become both the center of attention at fashion week - they were nominated for a Council of Fashion Designers of America award as emerging designers earlier this year - and on the red carpet, with celebrities like Sarah Jessica Parker and Brie Larson wearing their designs to major events like the Met Gala and the Oscars. Interest in their spring collection exploded after de la Renta chief executive Alex Bolen announced in September they will return this fall, this time as creative directors. To accomodate demand, they had to move their spring show to a larger venue in Chelsea, quite the change of scene from the cramped Norwood Club where they first showed exactly a year ago.

Kim joined de la Renta thirteen years ago when she was fresh off Pratt Institute and eventually became the late designer's design director, where for a time she was Garcia's boss when he joined as an intern. While he was there, he became the go-to-guy for de la Renta's many celebrity clients.

"I learned a lot from working with the stylist Kate Young about how to evolve the brand to work with what her clients wanted to wear on the red carpet," Garcia said."Actresses are real women. They want to show their waist, but they don’t want to look like they’re trying too hard." Lady Gaga, Selena Gomez, Kerry Washington, Jessica Chastain, Lupita Nyong’o became some of his clients.

The designers became close to de la Renta, but when it came time to find a successor in light of his failing health, the Belgian Peter Copping was selected over Kim. Now, they've come full circle. Their joining de la Renta as creative directors means their young label will benefit from the atelier's production savvy and expertise.

At the studio hours before their show, the designers took a breather from zhooshing with the collection. Kim, statuesque and slim in an Adidas tank top and Monse skirt, and Garcia, sporty and trim in his trademark jeans and t-shirt, embodied the attitude of their ideal customer, a stylish but practical downtowner with a playful streak. "The Monse girl is busy," said Garcia. "It’s about having a look that can go from working hours to putting on a red lip and a nice shoe and going out. Our girl likes to stay out late, but she’s not irresponsible. She has to go back to work the next day."

Though they have been working in tandem for nearly a decade – and were briefly engaged – Kim and Garcia have their differences, a ying and yang that's reflected in their designs.

“What’s funny is that Fernando is more feminine and I’m more masculine, so it’s a good juxtaposition,” Kim told me. When I asked them if they disagreed on anything in the making of the collection, Fernando said they disagreed on a few things. Meanwhile, Kim mischievously said they disagreed on "everything, like all day long.”

"I like to make the collection as short as possible," said Garcia. "I’m the kind of person who doesn’t like to overly articulate things. Like, if you have a point of view about khaki and pinstripe suiting, you can do it with three looks." Kim, on the other hand, is more free-flowing, both on paper and in the studio. Garcia also used to live in their old studio space, which made things a lot more about work than play for him. "I drive everyone a little crazy," he said, laughing. "I need to learn to separate work and personal life."

The duo's relationship can be summed up in a single look from the spring collection: a pinstripe shirt dress split down the middle with two different colors and hemlines. Holding it together is a thick waist belt, which is engineered to match both patterns in exactly the right spot. It's a piece that works from every angle, all day and all night.

Minutes before their show at ArtBeam in Chelsea, the designers were as cool as they had been that morning. There was more of everything this time - bigger crowds gathered outside, more sponsors (TAG Heuer and The Ritz-Carlton Rewards Credit Card among them) and more press. The anticipation ran high, but Kim was out front hugging and kissing their crowded front row, which included Bolen, Brandon Maxwell - who had beat them for the CFDA's Swarovski prize - and the actresses Christina Ricci and Zosia Mamet and even television crews. "I love the fact that they’ve taken a classic men’s shirt and done something so zany with it," said Mamet. "They’re playing within the realm of tradition, which isn’t something you see done well that often in fashion." Despite the heat, Kim never once broke a sweat.

At their after party in the Meatpacking District later on that night, she nearly fell into Garcia's arms when they finally found each other in the crowd after hours of schmoozing. They were beaming, but already thinking ahead to their big homecoming to de la Renta's, where they will deliver their first collection in February. "We just want to make sure that the Oscar woman also looks like she’s having fun," said Garcia.

At the end of the night, Kim escaped into an empty room for a moment's peace. "Where are we right now?" she asked, trying to text her friend the address. The day after the show she planned a facial and after fashion week, she's heading to Seoul for the first time in ten years to visit her grandmother, the woman who first taught her to sew.

But in that moment she was the prototypical Monse girl, deftly balancing work and play, personal and private. After a brief pause, she fixed her skirt and walked back out into the crowd, where a fan immediately asked for a "drunk selfie" with her and Garcia.

She smiled: "Of course."

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