(CNN) Joaquin Phoenix is not joking: He's really planning to wear the same outfit to every awards show this season.

That's according to designer Stella McCartney, who announced on her official Instagram account that the "Joker" star would wear one of her tuxedos for the whole season to help the environment.

McCartney revealed the news in the caption of a photo showing Phoenix with the Golden Globe he won for Best Actor in a Motion Picture - Drama.

"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," McCartney wrote. "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," she added.