Asked the secret to her happy marriage, she told Britain's HELLO! magazine: "Probably that I don't talk about it! It really is a secret.
"But maybe it's because we're not a Hollywood couple. We live in New York – maybe that's good."
The 60-year-old actress has always felt "insecure" about her appearance but doesn't care anymore about what people say.
"I've always been insecure about my looks, so nothing has changed. But I'm happy. I don't mind," she said.
"Every day when I leave the house, I have to think twice about how I look.
"I know I'm going to run into someone with a camera and have to worry about whether I ant to wear my favourite baggy pants or what my hair looks like."
Though Parker finds it "flattering" to be regarded as a style icon, she insisted other people's perceptions had never had much influence on her choices.
"It's flattering, but it's something I don't really think about," she said.
"I do love clothes and fashion, but I don't go out to be anything other than myself.
"There's a time when you're young when you think a lot about people's opinions of you, but I'd be at a disadvantage to spend a lot of time thinking about what other people think of me now, good or bad," she said..
And the actress insists her wardrobe isn't particularly fancy.
"I like to wear things that are comfortable and that I like myself in, that fit me well and convey the mood and feeling I want to express.
"[At home] I will probably be in my nightgown for a while and then, if I don't have to be very presentable, I'll be wearing jeans or corduroys or a light dress.
"Nothing very fancy. Nothing that I care much about, because it's bound to get dirty."
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