She’s the actress-muse-thinker-chameleon-alien who can spin gold out of the smallest indie film or biggest Hollywood production, as when she won an Oscar for her role as a ruthless lawyer in Michael Clayton. Tilda Swinton remains the strange and strangely alluring Scotswoman with a degree in poli-sci and thespian roots that go back to the 80s, when she worked with the late, great cult-film legend Derek Jarman.

She’s always up for the odd project, which these days are as likely to involve fashion as film; in 2003, for instance, she opened a Viktor & Rolf show in which each model thereafter was made-up in her pale-cheeked, red-haired image. Now a severe-cut blonde with another transfixing portrayal of self-awakening in the upcoming Italian drama I Am Love (or Lo Sono l’Amore, written/directed by Luca Guadagnino), the iconoclast is creating interesting work with the knit label Pringle of Scotland, which is where this interview begins.

Your collaboration with Pringle of Scotland is intriguing. I love the video you made with Ryan McGinley and Neville Wakefield, with its castle ruins and craggy countryside. Can you tell us about the creative process there and how important it is for you to work with Scottish companies?

The invitation to work with Pringle seemed to me a unique opportunity, a fit so good that it felt indecently easy to accept. My family comes from the Borders of Scotland, not far from the Pringle mill. My grandmother’s twinsets are amongst my most treasured inherited possessions. The legend—and the fact—of Pringle as a Scottish brand ranges, uniquely, from grand ladies and their granddaughters to football fans and golfers, let alone grazing American tourists. When Ryan and I started to conceive our film for Pringle last summer, we started and ended with the idea of homeland, landscape and sky. We shot it very near to where I live in the Highlands. In one day, and within a scope of a few miles, we had all our environments—woodland, sea, hill and ancient rock-built fortress—and all that inspiring range of beauty and heritage. It couldn’t have been easier.

I was in Glasgow for the first time recently (via the fine and generous folks at VisitBritain) and I got the impression that Scottish women are independent, sometimes eccentric, dressers. They keep up with fashion yet love their Harris tweeds. How much has this Scottish tradition informed your personal style? Or is it uniquely your own?

I would say that, for most Scotswomen, the basic mother’s milk of great cashmere, tweed and fantastic charity shops in every village across the country is key. Also, I would suggest the four-seasons-in-one-day nature of Scottish weather gives an opportunity for super-creative combinations. Inspired style in the Northern Hemisphere generally starts with the concept of cozy. Also, the idea of eccentric is an imported one, an English—or maybe, more recently, American—concept, foreign to the Scots, to whom the idea of conforming is anathema.

In your new film, I Am Love, your character sheds her clothes not just literally but figuratively when she begins her new life, or resumes her former one. What did you and the designer [Raf Simons for Jil Sander] discuss in terms of clothes that would reflect the transformation?

We worked very closely with the designers on a complete wardrobe for Emma, the woman I play in I Am Love. We wanted to give her a sense of being in uniform when clothed, of being subdued by her clothes, defined by them in a kind of submerged state of disguise. She is something like an avatar, a carrier for the past twenty years of programs not of her own design. Married into a super-conservative milieu, conformity is paramount. It is when she starts to reach for her own authentic life, her liberation from this confinement, that the clothes—and most crucially, the jewels that we have seen being put on her physically by her husband—must transform, before she has them taken off her, and finally takes them off, herself, forever. With Raf, we mapped a sort of color transition for Emma, as if the color palette of her dresses is directly wired to her unconscious. We gave her a red dress to fall in love in, the extraordinary tangerine orange dress when she first encounters the Eden of the garden, and, at a particular, unmentionable moment of tragedy, a dress the color of marble, which subtly changes its shade—lighter to darker—from scene to scene, before and after the crucial event, as if becoming, in an instant, flooded with grief.

When you’re first conceiving a role, how much are the clothes a part of your thoughts?

Very central. After the whole question of what body is necessary comes the issue of how the person in question dresses him/herself. In film, one works very fast to create a visual shorthand. It is in the first few minutes of any time spent with a character that the audience must become familiar with their universe. But, as in life, the details of how any one individual expresses their relationship to the world around them are easily plantable in their clothes and the decisions, conscious and otherwise, they make when presenting themselves physically. I see it as a very precise kind of forensic science and take a great deal of time and pleasure in this aspect of the work.

You seem able to radically transform yourself on film with choices of clothes and hair, but not make-up. How deliberate is it that your face remains essentially unchanged from movie to movie, and even from life to the movies?

I have a great interest in the concept and practical magic of transformation. It is the lion’s share of the work I make, the mapping of the particular moment of transformation in a story. Generally speaking, the moment of transformation that interest me the most tends to take the character into a place of revelation akin to laying bare, a sort of stripped-away encounter with authenticity, a crossroads from which all further roads lead. A good bare face is, to my mind, the best tool I—or any of us—have to explore this.

Are you able to keep (or accidentally walk off the set in) any of the pieces made for you?

I have one piece from every film I have ever made. My children have a secret trove waiting for them.