The actor and 'A Perfect Day' co-star Benicio del Toro sat down with ET on Friday.
Tim Robbins played a prison inmate in The Shawshank Redemption in 1993, and the experience has stuck with the actor ever since.
"I talked to some of the prison guards who were working as extras in the working prison," Robbins recalled of shooting Steven Spielberg's iconic film. "They told me something in '93 that's unfortunately stuck true today, and that's that we're over-incarcerating people."
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Robbins' experience inspired him to reach out to prisoners through his nonprofit group, The Actor's Gang, which seeks to "unlock human potential in the interest of effective rehabilitation" and reduce recidivism through eight week workshops with inmates in the California prison system. Robbins told ET he hopes to continue expanding the "very effective" program on a larger scale in the future.
“There's too many people who are in prison for too long of sentence, that haven't done things that are commensurate with that," he added. "So you have non-violent offenders serving 12 years in jail for possession of marijuana. This is not a good situation.”
The actor and activist sat down with co-star Benicio del Toro to promote their new movie, A Perfect Day, in which the two play aid workers in a high-pressure conflict zone. The film is a "window into a world we don’t often see" according to Robbins.
"Most of the people I met that actually do this work -- people that rush toward the fire -- there's a little bit of madness in them," he added. "Great madness, but they're pretty funny, too."
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For del Toro, finding the humor in the movie's tough subject matter was one of the most challenging parts of his role.
"It's a way of dealing with the darkness of the job, and it's a self-defense mechanism,” he said. "The humor was, for me, the thing that I felt like was the trickiest thing in the movie."
A Perfect Day hits theaters Jan. 15.
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