They may have transcended the ‘child star’ tag to become critically-acclaimed designers, but the Olsen Twins remain best known for their unique personal style. Often described as ‘eccentric’, the duo’s signature look - big sunglasses, bigger handbags, tiny frames loaded with layers and layers of clothes – has gone beyond iconic, influencing everyone from to Karl Lagerfeld. So how do the best-dressed get dressed? What inspires Mary-Kate and Ashley when they go shopping? ELLE’s April cover stars tell us all.

So how do you feel about the style icon tag?

Ashley: It’s a nice thing, of course, but we just don’t really think about that stuff. It doesn’t impact at all on how we dress. It’s like picking ‘Sexiest Man Alive’ – everyone has a different view. It doesn’t really mean anything.

Mary-Kate: It is flattering, though.

Do you ever stand in front of your wardrobe in the morning and think: ‘I have nothing to wear?’

Mary-Kate: Yeah! Of course we do – like everyone else.

How do you shop? Do you plan what you’re going to buy?

Mary-Kate: It’s impulsive for us. We don’t order anything from designers straight after the shows, for example.

Ashley: We can just go out and shop in New York – we don’t get bothered in the street much. The only difficult thing is finding the time.

Mary-Kate: The only planning we do is if we’re going vintage shopping and looking for something specific.

Is that what you enjoy the most?

Mary-Kate: You just never know what you’re going to buy. That’s why it’s exciting.

Ashley: You’re looking at things that may be one of a kind, or something that you loved 15 or 20 years ago when you saw it on the catwalk first.

Mary-Kate: It’s a different way of shopping. You’re not thinking about whether it’s on sale or who else has it.

Do you know what you’re looking for when you go vintage shopping?

Ashley: We both have a pretty good memory for catwalk moments and pieces.

Mary-Kate: We’re both attracted to certain eras – for Ashley, it’s Fortuny and early Chanel. I love Gaultier and Galliano.

Do you shop for vintage everywhere?

Ashley: We try to see what’s happening in LA, New York and also Paris.

Do you have things in mind that you’d like to collect?

Mary-Kate: It’s more about what’s out there. I might be attracted to something in a show but not buy it, then see it years later by which time it feels right.

Ashley: Having a good memory for fashion, sometimes you find that everything new looks the same. You can reference everything – it looks like a big mix of this show and this show. Nothing seems that original. That’s why we love vintage so much.

You don’t ever work with a stylist, do you?

Ashley: When we were kids, we each had to be in 20 looks a week for our TV show so someone obviously found the clothes for us. Now we dress ourselves.

It’s really surprising that you don’t hate fashion now, after all that!

Mary-Kate: On the contrary, we learned so much about clothes because we were so petite that everything had to be remade to fit us.

Ashley: That’s really how started. I never liked one full look from anywhere.

Is The Row still very much about the things that you want to wear?

Ashley: We don’t make items like a personal shopping list! We just want to create beautiful things.

Read Avril Mair’s interview with Mary-Kate and Ashley Olsen on giving up acting, their strongest partnership and pursuing modesty in the April issue of ELLE, on sale now