Princess Kate made a bold fashion statement on Friday at the Earthshot Prize Awards green carpet in Boston.

The Princess of Wales wowed in a neon green off-the-shoulder gown with her husband Prince William by her side.

In the spirit of the Earthshot Prize Awards, and with the event's sustainable fashion guidelines in mind, Kate's dress, designed by Solace London, was rented from the U.K.-based fashion rental platform HURR.

PHOTO: Catherine, Princess of Wales and Prince William, Prince of Wales attend the Earthshot Prize 2022 at MGM Music Hall at Fenway, Dec. 02, 2022 in Boston.
Mike Coppola/Getty Images
Catherine, Princess of Wales and Prince William, Prince of Wales attend the Earthshot Prize 2022 at MGM Music Hall at Fenway, Dec. 02, 2022 in Boston.

Kate paired her gown with an emerald choker necklace, matching earrings and sparkling heels.

William opted for a classic tuxedo with a black bowtie.

PHOTO: Britain's Prince William and Kate, Princess of Wales are greeted by Hannah Jones, CEO of the Earthshot Prize, as they arrive for the the second annual Earthshot Prize Awards Ceremony at the MGM Music Hall at Fenway Park, Dec. 2, 2022, in Boston.
Mary Schwalm/AP
Britain's Prince William and Kate, Princess of Wales are greeted by Hannah Jones, CEO of the Earthshot Prize, as they arrive for the the second annual Earthshot Prize Awards Ceremony at the MGM Music Hall at Fenway Park, Dec. 2, 2022, in Boston.
PHOTO: Britain's Prince William, Prince of Wales and Catherine, Princess of Wales, attend the second annual Earthshot Prize Awards at the MGM Music Hall at Fenway, in Boston, Dec. 2, 2022.
Katherine Taylor/Reuters
Britain's Prince William, Prince of Wales and Catherine, Princess of Wales, attend the second annual Earthshot Prize Awards at the MGM Music Hall at Fenway, in Boston, Dec. 2, 2022.

Many noticed Kate's necklace was one once worn by the late Princess Diana, William's mother. The choker necklace, which has an art deco design and diamonds, previously belonged to Queen Mary, Queen Elizabeth II's grandmother, who was gifted the piece in 1911. Diana received the diamond and emerald necklace from Elizabeth as a wedding present.

Diana wore the iconic necklace on several occasions, including to a gala in Melbourne, Australia, in 1985, where she wore the heirloom as a headband.

PHOTO: Diana (L) and Catherine, Princess of Wales are seen on a side by side picture.
Left: Tim Graham Photo Library via Getty Images/ Right: REUTERS/Katherine Taylor
Diana (L) and Catherine, Princess of Wales are seen on a side by side picture.
PHOTO: FILE - Diana, Princess of Wales, wearing a green satin evening dress designed by David and Elizabeth Emanuel and an emerald necklace as a headband, attend a gala dinner dance at the Southern Cross Hotel, Oct. 31, 1985 in Melbourne, Australia.
Anwar Hussein/Getty Images, FILE
Prince Charles, Prince of Wales and Diana, Princess of Wales, wearing a green satin evening dress designed by David and Elizabeth Emanuel and an emerald necklace as a headband, attend a gala dinner dance at the Southern Cross Hotel, Oct. 31, 1985 in Melbourne, Australia.

Earlier this week, Kate paid tribute to Diana with a pair of the former Princess of Wales' sapphire and diamond drop earrings as well.

The Earthshot Prize Awards mark the end of the royal couple's three-day Boston tour. The award ceremony honors those tackling challenges posed by climate change and the threats to the world's oceans, air and land.