Early reviews for James Mangold’s “Logan” have flooded the internet over the past week, and the prevailing opinion seems to be that the upcoming Wolverine solo movie eschews many of the superhero movie tropes in favor of a more grounded approach. It’s a more adult film, and there's a good reason for that.

Hugh Jackman spoke with USA Today about how he prepared for the role, which will be his final portrayal of the fast-healing, claw-wielding mutant Wolverine. It may come as a surprise that Jackman’s list of influences did not include the likes of “Captain America: Civil War” or “Batman v Superman: Dawn of Justice.” Instead, the actor said he found inspiration in dramatic films starring embattled protagonists, like “Unforgiven,” “The Wrestler” and “Shane.”

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“My basic belief is the harder shell you find on someone, obviously the more damage there is inside,” Jackman said. “It was about hooking into that.”

“Logan” director James Mangold said he found inspiration for the character in singer-songwriter Johnny Cash, which explains why the first trailer for the film featured Cash’s cover of a Nine Inch Nail’s song, “Hurt.”

“Logan” takes place in a near-future dystopia in which mutants are all but extinct. To survive, Logan and his mentor, Professor Xavier (Patrick Stewart), keep to the road, just barely scraping by as they try to stay off the radar. Their tenuous grasp on anonymity starts to crumble, though, when a young girl (Dafne Keen) sporting mutant powers like Logan’s (as well as a set of retractable claws) shows up on the scene. Torn between his desire to help the girl and stay hidden, Logan must decide if he will fend off the girl’s paramilitary pursuers or hand her over.

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The plot shares key similarities with the films listed by Jackman, which largely star self-destructive antiheroes past their prime who are wholly disinterested with fame. Such was the case with Clint Eastwood’s 1992 film “Unforgiven,” which saw a retired Old West gangster roped back into his old trade for one last job. Similarly, Darren Aronofsky’s 2008 film, “The Wrestler,” saw Mickey Rourke playing a washed-up wrestler coping with the reality of everyday life after never truly achieving fame. Jackman was so adamant about getting his role in “Logan” right that he took on an acting coach for the first time.

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Debuting in theaters March 3, “Logan” is a production of Marvel Entertainment directed by James Mangold and starring Hugh Jackman, Patrick Stewart, Richard E. Grant, Boyd Holbrook, Stephen Merchant and Dafne Keen.