Costume designer Jacqueline Durran pored over countless images of Princess Diana to get a feel for her clothing and style before meeting with “Spencer” director Pablo Larrain.

Durran, whose credits include “Atonement” and “Little Women,” grew up in the U.K and remembers that though Diana was a style icon to many, her look wasn’t admired in the same way as Kate, Duchess of Cambridge or Meghan Markle. Durran’s style boards featured plaids, block colors and other outfits worn by the Princess to help craft Kristen Stewart’s wardrobe.

Chanel also played a hand in collaborating with Durran, opening the archive to the film and to the costume designer. Durran talks about the iconic cream dress featured in the film’s poster and how the fashion brand played a part in building that dress.

“Spencer” is out now in theaters.

Pablo Larrain and Kristen Stewart in “Spencer.” Costumer Jacqueline Durran wanted to create Diana’s aura with her designs. Frederic Batier

Diana was so iconic, but as a fellow Brit what did she mean to you?

Maybe you’d understand this, but when I was in England and growing up, I was wasn’t that interested in Diana, and by that, I mean, she was a member of the Royal family, so I didn’t take much notice of what she was. I had never really delved into her costume in any detail before.

We weren’t that interested in the royal family when we were growing up, but you glazed over it because it was a part of our lives. We understood the Sloane Square Range Rover crowd, but it wasn’t something you tried to emulate.

When the poster dropped, were you on social media to see the reaction?

I’m not very good at that because I don’t have any social media. I was just oblivious to it, but people did call and send me text messages, but it was a bit of an event. Then the trailer came out. I did look at it, and I was thrilled with it because it is such a strong image. That costume ticked all the images because it’s one of the pivotal dresses. I wanted it to be light-colored and a fuller hem because it goes through all these passages – from getting dressed, to the hallways, to the outside and the derelict house. It had to work in so many different settings.

Where did you begin when conceiving the look for the film with Larrain?

He said, ‘The wardrobe is really important and it’s very specific. I want us to be very coordinated in terms of when we’re using different costumes. the context in terms of the sets, and the context of the DoP, and I want it to be very planned.’

He was in Chile, so I had a few weeks before I met him. I set about trawling through picture after picture of her on Getty Images and other online sites to get a sense of how she made her choices in clothing and the kind of thing she chose over and over again, and the themes in her look.

II had these boards where she was doing block colors, geometrics, plaids or contrast lapels, and she was doing them repeatedly. I was putting in colors specifically so that we could talk about what Pablo wanted to pull out and what he thought would be a good structure.

We pretty much prepped a costume for each of the scenes of the film and had a long nine-hour fitting with Kristen. We put the costumes in order and we more or less stayed on track. We had the bare bones done, and we didn’t deviate too much.

The place where we had the options to find new things all the time was in the montage. Pablo had this idea that we had the structure and story arc. The montage was a parallel thing where he said he would shoot Kristen in an extra costume every day of the shoot. I was constantly looking for vintage pieces that I could buy that he could then use just for these flashbacks of her that he ended up using towards the end of the film. But at the time I didn’t know how he would use it when we were shooting it.

You’ve mentioned working with Chanel. Kristen is also an ambassador for the brand, but how did Chanel weave itself into your work for this?

I’ve worked with them before, and when they get behind a project, they’re so great to collaborate with. We approached them and asked if they would be interested, but I sent a wish list and they sent a whole lot of things that we were looking for from the Chanel archive.

That’s where the pivotal cream dress came from – the archive. It was an original Karl Lagerfeld from the mid-’80s. When we put it on, it was just something that worked in terms of the idea of her as a princess, and it worked for all the things we were hoping for. But it was far too precious for us to use. Chanel said we couldn’t use it outside and that it could only be worn for a certain number of hours. In the end, they said they would make it for us in the couture workroom. They made a fantastic, perfect replica of the original, and that was the dress for the movie. So, Chanel was supportive.

Most of the Chanel that Diana wore was later, but one standout costume was from 1988 that Diana wore when she was in Paris. It was a red Chanel hat and coat. They had something from the archive, and that was something they sent over. It didn’t fit Kristen, but the color was great, again they remade the coat in her size. It’s the same style and the same fabric and we used it for our Sandringham Christmas morning coat.

We mixed it up in the film. We weren’t doing “The Crown” in any way, shape, or form, and we knew Diana didn’t wear that to Sandringham, it was about finding things that created the aura of Diana, her style or what she could have worn and putting them in the order that we wanted for the movie.

What kind of creative license did you have in portraying some of her famous outfits or did you try to stick with what had actually been worn?

I think I wanted to do both. I wanted it to have some moments where you nailed Diana so that the audience would almost think, ‘Oh yeah, well that’s that she did wear that.’ And then you could veer off quite far and just do something else that was the in the spirit of Diana, but it fits into the story that we’re telling about this woman, and you don’t need to be worrying about the minute by minute record of what she was wearing at any given time.

Do you have a favorite outfit or look that you put together?

I loved the plaid jacket she wore at the beginning. It was so hard to find a plaid that was that big. I was searching everywhere and could not find it. But, I found some in Cyprus, and they only had one jacket length. I bought the wool in Cyprus, and it had to ship it, but because it was COVID it was a nightmare, and when it arrived there was so little of it. I had to make the jacket, but then I had to make a double for the driver. But I love it because it was made from ‘80s fabric.

I also love the bomber jacket she wears to the beach. I found that online for sale. I have a photo of Diana wearing that exact jacket, and so it was entirely accurate.

How did you want costume to reflect her emotional state?

I didn’t really do that. I wanted the costume to completely support Kristen in whatever she wanted to do in each scene. I wanted it to be a rock-solid framework so that she would know exactly what was coming each time, and it would just be part of the structure for her and fully support her. I think her performance is phenomenal. I didn’t plot it that way. I think in those stories what is useful is a dissonance between the costumes and what’s happening to the person.

Kristen Stewart channels Diana in vintage plaid. Neon/Topic Studios