In: New York

And in Wicked, which opened on Broadway in 2003, that world is incredibly detailed. The musical reimagines The Wizard of Oz from the perspective of the witches, and from her first creative meetings, Hilferty knew she wanted to honor the show’s magic by giving each character an utterly unique appearance. That means every costume is tailored to fit the actor who wears it, and that even the ensemble members have one-of-a-kind looks. If you’re at the show, pay careful attention to scenes in the Emerald City: All of the townspeople wear green, but every woman’s skirt has an individual cut, and every man’s hat has its own special brim.

Of course, the costumes begin with Hilferty’s personal vision. In one key scene, Elphaba, who becomes the Wicked Witch of the West, learns to fly while wearing a dramatic black dress. Hilferty not only created the shape of the costume, but also designed its fabrics herself. (There are over thirty materials in that outfit alone.) “Each piece of the dress has to have a certain weight and texture,” she explains. “And even though it’s black, there are potentially a million types of black fabric. You have to decide which black you want.”

From there, collaboration becomes vital. Wicked has almost three hundred costumes, and each one is hand sewn. When a new actor steps into a role, he or she gets a fresh batch of clothes, and the sewers inevitably brings new facets to a garment, adding, say, their own flair to the cross-stitching on a bodice. Hilferty approves every piece, but she must trust the craftspeople to bring her vision to life.

She says actors also affect her designs  “I’ve got to remember that I’m messing with another human being’s sense of themselves,” she explains. “I have to ask them, ‘Will this costume correspond with the inner character you’re creating?'” As an example, she notes the variety of actors who have played The Wizard of Oz. Some, like Oscar winner Joel Grey, bring their dance background to the role, and they need costumes that allow graceful movement. An actor playing a more “realistic” Wizard, however, doesn’t require that kind of freedom.

Hilferty has even worked with Wicked’s sound designer, so that the material in a hat won’t distort the microphone fastened in an actor’s hairline. “There’s no way to know which fabrics will affect the sound,” she says, “You just have to test it until you get it right.”