Joaquin Phoenix will be wearing the same tuxedo through this year's awards season in an attempt to reduce waste.

British designer Stella McCartney revealed that she was joining forces with the "Joker" star "to make choices for the future of the planet."

Phoenix discussed climate change during his acceptance speech at the Golden Globes, telling his fellow stars to stop taking private jets.

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From the plant-based dinner to numerous speeches that mentioned the Australian bushfires, climate change was a major topic at the Golden Globes.

Following Sunday night's show, it has been revealed that Joaquin Phoenix is planning to wear the same tuxedo throughout this year's awards season in an attempt to reduce waste.

The news was shared by British designer Stella McCartney, who wrote that she was "proud to join forces" with the "Joker" star.

This man is a winner… wearing custom Stella because he chooses to make choices for the future of the planet and all of its creatures. He has also chosen to wear this same Tux for the entire award season to reduce waste. I am proud and honoured to join forces with you Joaquin, keep inspiring and keep shining your light x Stella⁣ Joaquin Phoenix wins Best Actor at the 77th Golden Globe awards, wearing a custom #StellaMenswear Tuxedo.⁣ . #JoaquinPhoenix⁣ #StellaMcCartney⁣ #GoldenGlobes #InStella A post shared by Stella McCartney (@stellamccartney) on Jan 6, 2020 at 3:09am PST Jan 6, 2020 at 3:09am PST

"This man is a winner," she wrote in a post shared to both Twitter and Instagram. "Wearing custom Stella because he chooses to make choices for the future of the planet."

"He has also chosen to wear the same tux for the entire awards season to reduce waste," she added. "I am proud to join forces with you."

Stella McCartney calls itself a "sustainable luxury fashion brand" and McCartney herself is vegan. The company never uses leather, skin, fur, or feathers.

Joaquin Phoenix poses in the press room at the 77th annual Golden Globe Awards at the Beverly Hilton Hotel on January 5, 2020. Steve Granitz/WireImage

"By taking this stance, we are proving it is possible to create beautiful, luxurious products that are better for everyone — animals, people, and the environment," the company's website reads.

The label also uses a tool called the Environmental Profit and Loss (EP&L) to measure its impact on the environment from "greenhouse gas emissions, water use, water pollution, land use, air pollution, and waste."

Phoenix himself discussed climate change, and the negative impact Hollywood has on it, during his acceptance speech on Sunday after winning best performance by an actor in a drama film.

The actor first thanked the Hollywood Foreign Press Association for "recognizing and acknowledging the link between animal agriculture and climate change" by choosing to serve a 100% plant-based dinner during the show for the first time in its 77-year history.

"It's a very bold move making tonight plant-based, and it really sends a powerful message," he said.

Phoenix then called on his fellow stars to do more than just mention Australia in their speeches as the continent continues to grapple with devastating bushfires.

Joaquin Phoenix gives his acceptance speech at the 2020 Golden Globes in Beverly Hills, California. Paul Drinkwater/NBCUniversal Media, LLC via Getty Images

"It's really nice that so many people have sent their well wishes to Australia, but we have to do more than that," he said. "Hopefully, we can be unified and actually make some changes."

"Sometimes we have to take that responsibility on ourselves and make changes and sacrifices in our own lives," he added. "We don't have to take private jets to Palm Springs for the awards."

Phoenix may have been inspired in part by his fiancé Rooney Mara, who opted to wear a Givenchy gown from the label's spring 2019 couture collection instead of a brand-new custom dress for the show.

Rooney Mara and Joaquin Phoenix walk the red carpet during the 77th annual Golden Globe Awards. Getty Images / Frazer Harrison

Clare Waight Keller, Givenchy's current artistic director, has also spoken about her own efforts to make the brand more sustainable by using organic and recycled textiles.

"We need to wear our clothes for longer," she told Vogue. "It's the throwaway aspect which is destructive."

Representatives for Joaquin Phoenix and Stella McCartney did not immediately respond to Insider's request for comment.