'I'm pretty careful about my hair. I see David Adams for color—he’s the best hair colorist I’ve ever seen. He has a very gentle hand, a very natural stroke. He brings a natural dimension to hair that I’ve been seeking for a really long time. He took me red for the last role I did, for a film [Still Alice] with Julianne Moore, which was a huge change. I loved being a redhead; I noticed my eyes more, having that shade against the blue and the green of my eyes. And then he just brought me back to blond three weeks ago. I have one more process to go—to come off of red you need a few processes, and you have to be very careful not to damage your hair. David is really, really brilliant and I don’t use that word lightly. He’s amazing at what he does.

I love Pureology and Aveda shampoo. My hair can feel weighted down or greasy very easily—it just takes to products so much and so heavily that it loses the thick feeling. And those two shampoo products work with my hair really well. But, I’m not someone who overworks my hair when I don’t have to. I often let it air dry. If I’m in a rush, I love Harry Josh’s hair dryer. My mom has one and I have one. He [Harry Josh] took my virginity in that way—I didn’t even own a hairdryer before Harry’s hairdryer! [Laughs]

Otherwise, I love SK-II Masks. They’re really fun to do with your girlfriends because they look so crazy. [Laughs] They’re cotton sheets dipped in a high level of pitera, which is the active ingredient in all SK-II products that’s derived from sake. You get this high-concentration of an active ingredient that saturates the cotton and you put it on your face. I put my masks in the refrigerator, so it can take away even more inflammation. It tightens, it brightens—it makes my face look like it’s had a good night’s sleep, when I could have had no sleep. It’s the best quick fix I’ve come across for skin.

When SK-II called me, I became fascinated with the whole range of products, but I was already using some. When people are connected to a brand, you always wonder, ‘Do they really use the products or not?’ I remember when the company called my agent, they said, ‘Can you ask Kate if she uses any SK-II?’ They really wanted to know if I was a fan of the product before I came on board. My agent casually asked me, ‘Do you use SK-II?’ He didn’t even tell me that the brand was asking. And I said, ‘Yes, I love their products, I’ve used them for years!'

I wash my face morning and night with the SK-II Cleanser. Always, morning and night. I also use the Facial Treatment Essence, which is beautiful. It’s water-consistency, so it’s super light, but it has the highest concentration of pitera of any of the products—90%. So, don’t let it fool you and think, like, ‘Oh, what's this water-like substance really going to do?’ It’s incredibly active and aggressive. It’s the most successful product they have. One bottle is sold every thirty seconds or something; it’s crazy.

So, I’ll cleanse, do the Facial Treatment Essence, or sometimes I’ll use the Cellumination Essence, which is a real brightening product. And then depending on where I am, I’ll usually use the LXP Serum and then the LXP Cream, which is like heaven. I asked my aesthetician, Faith Tatro at Touch of Faith Aesthetics in Los Angeles, ‘How do you know which product to use first?’ And she said it’s a molecular thing—you have to use the most watery substance first, and then the next thing should be the next thickness, and so on. It’s so that everything is penetrating the skin appropriately, which I actually didn’t know, and I’m sure a lot of people don’t, either. It turns out it’s really about the thickness of the product. Faith kind of does everything. I was always a bit weary of facials, because you don’t really know what they’re doing. But she’s so knowledgeable about skin that she can really look at everyone’s necessities and tailor a customized facial for them.

In terms of makeup, I definitely believe less is more. I’m constantly on the hunt for the best foundation. Right now, I like the YSL Touche Éclat Foundation. It has a fluidity and workability that keeps it sheer if you want, but you can also add a little bit more. I like Clé de Peau Concealer, for when you wanna bring out the big guns. In general, I keep it quite simplified. For lips, I like a stain, like the Tarte LipSurgence stains or the stains from By Terry. Some people like to just throw on some lipstick, like my mom, for example. But I like to work things in a little bit more and allow it to feel more lived-in, which is what you get with a stain. I like things a little bit...not messy, but something that feels like who you are, that moves with you...that it-doesn’t-have-to-be-perfect kind of thing.

I don’t want tons of layers and heaviness. I like being able to use my cheek product on my eye and my lip and just put on my favorite mascara, Le Volume de Chanel, and maybe a little bit of highlighter. I really love the RMS Living Luminizer. I can blend a little bit of that in with my foundation and just kind of tap it on. I like products that you can mess around with. For example, anything that looks scary-pigmented, I’ll be into because I know I can take a little and really work it into a flush.

In terms of fragrance, I’m really loyal to Byredo Gypsy Water. I’m dying to meet [Byredo founder Ben Gorham] because I’m really such a massive fan. His scents are beautiful and complex and sexy and innocent. There are such incredible layers to what he does. I’m a loyalist with my scents.”

—as told to ITG

Kate Bosworth photographed by Emily Weiss in New York on May 1, 2014. Visit the new SK-II Pop-up Studio open until May 23 in New York and San Francisco. For more information, click here.