Matt Damon was left out of all the marketing materials for Interstellar, but he ended up having a crucial role in Christopher Nolan’s sci-fi movie. In addition to being one of the most popular movie stars in Hollywood, Damon is known for showing up in unannounced cameo appearances. He appears in EuroTrip as a punk rocker singing the catchy tune “Scotty Doesn’t Know,” he's in Thor: Ragnarok as an Asgardian actor portraying Loki in a staged retelling of the previous Thor movie, and he’s popped up briefly in a bunch of Kevin Smith movies. But unlike those other cameos, Damon’s role in Interstellar isn’t played for laughs.

Interstellar is Nolan’s ambitious stab at a 2001-style space-faring epic. It has Nolan’s vision of a dystopian future, his vision of undiscovered worlds, and his take on a Star Wars-type sardonic droid sidekick. Matthew McConaughey stars as Interstellar's protagonist, Cooper, who leads an expedition to the stars in the near future to find humanity a new home when Earth finally becomes uninhabitable. The d cast also includes Anne Hathaway, Jessica Chastain, and Nolan mainstay Michael Caine. But there was a surprise appearance by Damon, whose unexpected ing role came with a shocking twist.

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Matt Damon Played Mann

Mann and Cooper on an alien planet in Interstellar

Matt Damon played the ironically named Dr. Mann in Interstellar. When Cooper and his team head to the second inhabitable planet that humans could relocate to, they are surprised to find that the astronaut sent to explore it is still alive. They awaken Mann from cryostasis, and he fills them with the hope that the planet he discovered could human life. However, he privately reveals to Cooper that this is a lie. He falsified the data so that NASA would send a crew to rescue him. After trying to kill Cooper and steal the Endurance spacecraft, one of the best sci-fi spaceships, Mann is killed in a failed docking.

Damon's Role Was Kept Secret For A Reason

Matt Damon wearing a spacesuit in Interstellar

Matt Damon’s role in Interstellar was more than mere stunt casting. Christopher Nolan told the Inquirer that he didn’t want to mislead audiences by putting Damon in the trailers because his role in the movie is very small —albeit significant. But the reason for keeping his involvement a secret goes deeper than that. The audience’s familiarity with Damon brought certain connotations to their experience of Interstellar. Nolan said, “I really love the idea for an audience to go, when they see him, ‘Oh, it’s Matt Damon. It’s going to be okay.’”

When viewers see Matt Damon, the actor behind such memorable characters as Will Hunting and Jason Bourne, they get a feeling of comfort and security. When he says his planet can human life, the audience implicitly trusts him. This was a great way to preserve the twist. Nolan explained, “Matt has the most amazing ability to project integrity and warmth. So, he turns up in the film, and he’s got a plan, and it’s all going to be okay.” According to producer Emma Thomas, Damon’s role in Interstellar rewards a second viewing of the movie: “It’s so great watching Matt when you know what’s really going on.”

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