Lily James Shot Her New Natural Diamond Council Campaign in -40 Degree Temps: ‘It Was Remarkable’ (Exclusive)

As the global ambassador for the Natural Diamond Council (NDC), Lily James has not only had the opportunity to wear some truly amazing diamonds on the red carpet (more on that later) but she’s also traveled the globe to witness first-hand how the dazzling stones are mined.

Her latest journey with the NDC took her to the Northwest Territories of Canada (the world’s third largest diamond producing region) to shoot the new “Real. Rare. Responsible.” campaign and learn more about their sustainable missions, their conservation efforts and their support of the communities where the diamonds come from.

Here, the actress talks to PEOPLE about her experience, which includes posing with a 33-carat round brilliant cut natural diamond.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

PEOPLE: What’s the best part of shooting a diamond campaign?

James: One of the most incredible things about shooting a diamond campaign is doing so with the Natural Diamond Council, and going straight to the origin of where natural diamonds were formed, billions of years ago.

Fascinated by my trip to Botswana with the Natural Diamond Council in 2022, I really wanted to learn more about the positive impact of the natural diamond industry around the world, which is why I visited the Northwest Territories (NWT) of Canada. I traveled to the remote Sub–Arctic in February, to shoot a campaign in –40 degrees Fahrenheit. While there, I witnessed firsthand how a large majority of rough diamond value remains within local communities in the form of local employment, training, sourcing of products and services, health and education programs. It was truly remarkable. 

I loved visiting Diamonds de Canada too, and seeing how they are keeping everything local from mining, cutting, and polishing of natural diamonds so that it increases the local benefit. They are the sole producer of the Polar Bear Diamonds which can only be found in Northwest Territories of Canada and are all sold with Certificate of Authenticity to prove their origin.

Having the opportunity to visit one of the world's largest diamond producing regions, and meeting women at the helm of mining operations, to educators shaping the future generation, everywhere I look I’m reminded that natural diamonds are truly real, rare, and responsible. 

PEOPLE: What was your favorite piece you got to wear in the campaign?

James: This campaign was unique in that I wasn’t wearing a lot of finished diamond pieces, but I did essentially live in these gorgeous one carat diamond stud earrings throughout the shoot, from dawn to dusk. We also spent a few days shooting with this incredible 33-carat round brilliant cut natural diamond. It’s so special to visit the birthplace of natural diamonds, while getting the rare opportunity to hold them, and feel their energy. 

The PEOPLE Puzzler crossword is here! How quickly can you solve it? Play now

PEOPLE: What’s the most memorable piece of jewelry you’ve worn on a red carpet and why?

James: I recently wore the most spectacular natural diamond feather earrings and rings from Boucheron to the Met Gala. They are from their ‘Plume de Paon’ collection, aptly named for their peacock feather design. They had such an incredible sparkle when the light hit them, it was such a treat to wear these for the evening.

PEOPLE: The Erdem gown you wore to the Met Gala was a PEOPLE style team favorite. What did you love most about it?

James: Not only was the beautiful blush pink gown my absolute dream Erdem dress, but Erdem Moralioglu is such a brilliant designer, and happens to be a dear friend. Having the once in a lifetime opportunity to dream up this work of art alongside the incredibly talented Erdem team is an experience I feel so blessed to have had. A moment in time, I will cherish forever. His creations belong in the Met Costume Institute. I’m endlessly inspired by every morsel of detail weaved throughout his designs. 

PEOPLE: What pieces of jewelry do you wear every day? 

James: My day-to-day jewelry can vary based on where I am and what I’m doing. I often wear small, dainty, hoop earrings. One piece that I do wear every day and is my most cherished diamond piece is a diamond locket. To me, family heirlooms feel eternal, sentimental, and ancestral. I know when holding them that it’s something that will stay in our family forever. Not only are diamonds unique and rare, they’re also Earth’s oldest heirloom.

PEOPLE: You’ve said that you love that beauty “feels like self-care and wellness.” What are some beauty products or treatments that you’re loving right now and what makes them so great?

James: I am really into self-care, especially with such a busy schedule, it’s important to find time for oneself. Something I consider a form of self-care is being amongst nature, it centers me.