Jane Fonda, Margot Robbie, Joaquin Phoenix and more send powerful message with Oscars looks

While stars like Margot Robbie and Saoirse Ronan had people talking about their gowns at the 92nd Academy Awards, the actresses made a statement bigger than just fashion. The Oscar nominees were among the many celebrities who made eco-conscious choices on Hollywood's biggest night. From recycling looks to using sustainable materials, it's clear that going green was the biggest red carpet trend Sunday.

When presenter Jane Fonda took the stage, she stepped out in a red beaded Elie Saab gown she previously wore to the 2014 Cannes Film Festival. The Grace and Frankie star had her infamous red coat draped over her shoulder, which she declared last year "is the last article of clothing I will ever buy." She wore that same red coat to every Fire Drill Friday. Fonda has been protesting climate change over the past several months after being inspired by teen activist, Greta Thunberg.

Joaquin Phoenix, who joined Fonda's protest in January and was arrested, used his time on stage to (graphically) highlight the climate crisis. When the Joker star accepted the Oscar for Best Actor, he did so in a recycled black Stella McCartney tuxedo. Phoenix pledged to wear the same tux throughout awards season, which he did. McCartney, who has been one of the leaders in the industry when it comes to sustainable fashion, also dressed Olivia Colman. According to Vogue, The Crown star’s gown was made with a sustainable velvet material.

Saoirse Ronan's dress was also eco-friendly. Gucci used the same black fabric from her BAFTAs gown to create part of her Oscars dress, per Vogue. James Bond Spectre star Léa Seydoux and Booksmart's Kaitlyn Dever both wore ethical and eco-responsible Louis Vuitton custom-made gowns.

"I’m here to support sustainable clothing," Dever told the Los Angeles Times, adding that she tries to "think before buying something new."

Costume designer Arianne Phillips worked with Moschino's Jeremy Scott to repurpose a gown she first wore to the 2012 Oscars.

Meanwhile, Elizabeth Banks and Ariana Huffington brought sustainability to the Vanity Fair party. Banks recycled a Badgley Mischka dress she wore to the same party in 2004 while Huffington re-wore the same dress from 7 years ago.

Margot Robbie is the biggest star who embraced a vintage look, wearing a Chanel dress from the brand's spring 1994 Haute Couture collection. While wearing vintage might not seem like the biggest eco-sacrifice, Mercari’s Chief Stylist Anna De Souza says celebrities are creating "meaningful conversation" with these fashion choices.

"There’s never been a time where fashion choices are so critically analyzed and celebrities are being urged to tap into the latest cultural trends, a huge one being eco-responsible dressing and second-hand duds," De Souza tells Yahoo Entertainment.

Mercari is a selling app and De Souza recognizes sustainable fashion is a growing focus in 2020, which includes "pre-loved garments." Celebrities are helping change the stigma around re-wearing old clothes.

"With the influx of fresh services making it easier than ever to rent and purchase pre-loved luxury and special occasion gowns but also everyday separates, celebrities tapping into this trend are able to create meaningful conversation with fans as well as publicity opportunities alike," she concludes.

Read more from Yahoo Lifestyle:

• Oscars 2020: What the stars wore on the red carpet

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