It’s tempting to conflate Kristin Scott Thomas with one of her many roles. That was especially true in her brief appearance in Fleabag when she voiced a killer soliloquy about the perils of living in a woman’s body. It starts with being “born with pain built-in” and caps off with a description of menopause as “the most wonderful fucking thing in the world.”

She tells me, “When I read that thing, I thought, Ah, this is what I have been longing to say. I take no credit for that because it was Phoebe [Waller-Bridge]. I just said the words.” But who else could deliver those words so believably, and with such power and style?

Now 65, Scott Thomas softens the hauteur with a flower crown in the new movie, My Mother’s Wedding, a film she directed from a screenplay she wrote with her husband, John Micklethwait. She plays the bride and mother of three sparring daughters, including Scarlett Johansson and Sienna Miller.

It’s quite a shift from her role in the television series Slow Horses as Diana Taverner, a British intelligence official with impeccable hair, lipstick, nails, and wardrobe. “That is her armor,” Scott Thomas says. “In so many cases, the way women present themselves at work, particularly, is a kind of shield. She is a fortress, and those are her walls and her ramparts. I think you’ll see some developments, little developments. I’m not sure I’m supposed to say that but.…” We don’t have to wait long to find out; the fifth season airs on Apple TV next month. —Linda Wells

I think your look is defined when you’re in your late teens and out of the grips of your parents. For me, that was in the 70s, and it was very punky. I’ve still got my hair standing on end.

I probably found my look in my late 30s. I was living in Paris and got quite into fashion. There’s something about French women’s laid-back, cool look that is really enviable. There’s also the other French woman who is impeccable, absolutely not a hair out of place. And that is for me impossible to attain, just impossible. And I’m very admiring of that.

I used to wear high heels all the time, like the higher the heel, the better I feel. That was my mantra through the 90s and noughties. And now I have an enormous variety of sneakers.

I’ve always had a penchant for quite big shoes, big platforms or men’s loafers and things like that. I love trousers. My favorite in the world is a pair of sailor trousers with the buttons that I bought 25 years ago from the Gap. In the beginning, they were navy blue and now they’re sort of gray navy blue, very washed out. If I’m going out of an evening, you’d probably find me wearing those trousers and a little German worker’s jacket that buttons up high. And I’ve always got on a striped T-shirt.

I love bracelets. In the old days, every time I made a film, I would buy myself a little piece of gold. I bought a very simple bangle at Tiffany’s in Washington after I did a film called Random Hearts. These rings I’m wearing, I bought after a theater show.

I’m very proud of my white hair. When I did The Darkest Hour, I played Clementine Churchill, and I had this beautiful white wig because she had white hair very young. I would take off this wig at the end of the day and think, Oh, really? I preferred life with it.

And then when it all started to go gray, I had to go to the hairdresser’s every three weeks [to get it colored] because my hair grows at the speed of sound. I thought, This can’t be good for me. So I decided to see what would happen if I just let it go white. And it happened so quickly. It’s just the front, so I can hide it. It’s nice, isn’t it? And I think that having light around the face when you start to get older is just good.

I do get recognized on the street. I get recognized on the tube. It’s not unpleasant. It’s not life-changing. But I only get recognized when I’m wearing lipstick. I do like the lipstick. I had to wear a wig once to go out, which was silly because I just felt so self-conscious. And then I got sort of angry about it because I thought, Why do I have to go out and feel bad just because I don’t want to be chased down a street by a man with a camera? That doesn’t happen anymore, thank goodness.

I hope I look better in my public life than in my private life. My mother always used to say, Darling, you must respect your audience. And, you know, she had a point. So I do, I do. I like to put a bit of polish on when I go out. I do enjoy the kind of hoodwinking that happens with really good clothes and hair and makeup. I enjoy being glossy. What’s fun is to be able to do it all, isn’t it?

I looked great in my early 40s. I looked great in my early 50s. And it’s just been downhill since then. It’s hard. You look at yourself in the mirror and you see lines and the saggy bits. I’m about to have my eyes lasered so I won’t have to wear glasses or contact lenses. I’m terrified about actually seeing the truth. There isn’t going to be a sort of sticky-fingered film. I’m going to see what everyone else sees, and I’m a bit scared about that.

It’s a weird thing to be ignored, especially when you are someone who really wasn’t ignored as a younger person. I think it started happening when I was about in my early 50s if I wasn’t sort of done up. If I didn’t have my film-star gear on, I would just get not seen. Where it really struck me was going into a building or something and somebody just barges straight past you. You do not exist.

But then you learn to live with that, too. And, then I think, poor them, right? They’ve got a shock coming.

I get a bit cross when I go into a shop and they call me dear. But I discovered the joys of people standing up for you on the tube and letting you sit down. And it’s all because of the white hair.

This quest for youth is a waste of time. The quest for looking healthy and happy, that’s what I would love to be able to enjoy.