Soon, the Avengers will return on the big screen to take the fight to Thanos and, hopefully, save the universe. Now, in the real world, two Marvel Cinematic Universe stars, Mark Ruffalo and Don Cheadle, want to save the world and make it a better place too.To celebrate Earth Day, the two actors revealed a newly, Marvel-licensed t-shirt that showcases the Avengers and benefits environmental organizations. Ruffalo and Cheadle are both board members of 100 Is Now, a campaign of the Solutions Project which is devoted to promoting climate justice and clean energy resources around the world.RELATED: Avengers: Endgame Has Reportedly Already Made $120 Million in Pre-sales"100% of the proceeds from these limited edition shirts support our commitment to climate justice & @100isNow," the actor tweeted. "A big thanks to @MarvelStudios & the entire #AvengersEndgame team for making this happen. Join @doncheadle & me now in the fight of our lives."

The campaign is also supported by the entire cast of Avengers: Endgame, as Chris Hemsworth, Chris Evans, Scarlett Johnansson and the film's other stars can be seen wearing these shirts on the Represent website.

The t-shirts feature eight Avengers, as well as the slogan "The Fight Of Our Lives." They are available in a variety of colors and models, all officially licensed by Marvel and will ship internationally. The shirts can be ordered until May 6, and shipping is set to begin May 24.

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Mark Ruffalo and Don Cheadle will both be seen in Avengers: Endgame, the Marvel film that will serve as the capstone to the first decade of Marvel Studios movies. While Cheadle joined the MCU as War Machine in Iron Man 2, Ruffalo stepped into the MCU as the Hulk in 2012's The Avengers.

Directed by Joe and Anthony Russo, Avengers: Endgame stars Robert Downey Jr. as Iron Man, Chris Evans as Captain America, Mark Ruffalo as Bruce Banner, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Brie Larson as Captain Marvel, Paul Rudd as Ant-Man, Don Cheadle as War Machine, Karen Gillan as Nebula, Danai Gurira as Okoye and Bradley Cooper as Rocket, with Gwyneth Paltrow Pepper Potts, Jon Favreau as Happy Hogan, Benedict Wong as Wong, Tessa Thompson as Valkyrie and Josh Brolin as Thanos. The film opens Friday worldwide.