In 2005, Kate, 33, and Laura Mulleavy, 31, the sisters behind Rodarte, cold-pitched their debut collection of 10 pieces to fashion editors in New York City through a set of paper dolls outfitted with miniature versions of the garment. Within days, the fashion trade publication Women’s Wear Day put them on their Feb. 3, 2005 cover; overnight, a pair of sisters with little formal training and no industry connections had become the buzz of New York City’s fashion scene. In the last seven years, they’ve branched out to design a diffusion line for Target, guest edit magazines and create costumes for 2010′s Black Swan. TIME spoke to the Mulleavys as they prepared to unveil the creations from their latest venture — costume designers for the Los Angeles Philharmonic’s Don Giovanni production — which premieres May 18.
TIME: Vogue editor in chief Anna Wintour asked for a meeting shortly after your first trip to New York City in 2005. What did she tell you?
Kate: She gave us the best advice we’ve gotten in our career. She could tell what we were doing was very personal, and she told us to keep it that way. Advice like that in the infancy stages was so crucial, and it’s a testament to Anna’s vision and commitment to American fashion. There are certain things that have led to our creative development — at a point where we were questioning how to do the thing we wanted to do — and that meeting was one of them.
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TIME: You also got the Don Giovanni gig on her recommendation. How did you find out about it?
Laura: We saw Anna at an event, and she just told us in passing that she recommended us for a job with Frank Gehry [the architect is designing the sets for Don Giovanni]. Then we got a call from the Los Angeles Philharmonic. It seemed so surreal even until we left Frank’s office. To go into the world of someone I think is such a genius — it was weird to step into the heart of it.
TIME: What was it like working with Frank Gehry?
Kate: It was one of the most interesting creative exchanges I’ve had with someone besides my sister. He was a kind of kindred spirit. You’re meeting an iconic artist, for one thing, and on the flip side, you’re meeting a warm, kind person who makes you laugh.
Laura: I always know our meetings with Frank are going to last four hours, and we’ll talk about the opera for like 10 minutes. Even when we’re talking about something that will ultimately be concrete, like a prop, the dialogue is abstract, and we know it’s always evolving and changing. We work that way. Frank works that way.
TIME: What inspired your thinking about the Don Giovanni costumes themselves?
Kate: It took a while to understand the characters, their motivations and what we wanted to visualize. Frank told us from the beginning that it was about the music, and our job was to help that.
Laura: The costumes are the kind of thing that you want to lift the music — you don’t want to compete or kill it. This music is so powerful throughout.
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TIME: You first ventured into costume design with 2010′s Black Swan. Tell us about that experience.
Laura: We wanted the costumes to convey the brutality of dancing — what you do to your body, and the way these athletes can defy gravity. All these things went into the costume choices. We had references from [post-minimalist sculptor] Eva Hesse to [Edgar] Degas.
Kate: It was an unbelievable undertaking to be totally hands on in the costume design process while we were doing our own runway show at the same time. But it’s funny, because two years earlier, we’d done a [fall 2008] collection about horror films and ballet. Then, we did a [spring 2010] collection about the California condor, which for us, is the demented version of the swan.
TIME: Your Don Giovanni and Black Swan costumes both emulated the couture-like pieces in your runway shows. Some critics have said your clothing isn’t wearable, suggesting that you might not care about the business of fashion.
Laura: It’s always easier to summarize someone else’s working process. We are very artistic. We’ll always take the artistic choice over the non-artistic decision. But everyday you’re dealing with the business side — it’s never removed. There’s no bubble you can live in and act like you can do this without running a business. In the past you could divide designers into super artistic or commercial, but I think fashion has shifted a lot between now and the early ’90s.
Kate: We made a conscious decision from the beginning that we weren’t going to take Rodarte in the first four or five years and expand it into all different areas. It takes time to understand who you are in clothing. I don’t pretend to know it overnight.
Laura: The industry moves so quickly now, and you can see everyone else’s work. So developing your work so that it’s recognizable is harder. The worst case, for us, would be having a costumer walk into a store and not be able to recognize our stuff from someone else’s.
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TIME: You guys obviously have a very close bond and are notorious for finishing each other’s sentences. Are you similar as designers, too?
Laura: Kate does the final sketches.
Kate: Laura can go with the flow — she’s great in the moment with draping and fittings. But we don’t lock each other into roles. There’s a freedom to who we are. Sometimes Laura’s the more organized one, and sometimes I am.
Laura: Her desk is a mess! I can’t work on it, and then she always wants me to come over there and work in her space.