The tension was palpable in the theater for Variety’s Screening Series even after “Foxcatcher” came to end. The 134-minute long psychological drama was bookended by director Bennett Miller’s offhanded explanation about the bizarre circumstances that led to the creation of the film.

“A stranger approached me in a store and handed me an envelope that contained newspaper clippings about the story,” Miller said tersely, recalling how he discovered the true story that informs “Foxcatcher.”

But the same tragic story (of sibling Olympic wrestling champions Mark and Dave Schultz and their millionaire benefactor John E. du Pont) that fascinated Miller initially repelled star Channing Tatum.

In fact, Tatum said he initially wasn’t interested in the role when approached about it seven years ago.

“To be quite honest, I didn’t understand exactly why he wanted to make it,” Tatum told the audience at a Q&A following the screening. “I just go like, ‘Wow, this is so dark.’ Bennett was kind of weird then. He’s a little better now. I just didn’t get it. I didn’t understand it.”

But Tatum couldn’t quite shake off the character of Mark, who he said lived in his subconscious for seven years.

“I don’t know what exactly happened in those seven years other than just a little bit more of an understanding of stories and why we tell them and what is fascinating about people and characters and relationships and just life,” Tatum said.

Miller said Tatum first caught his eye with his captivating performance in the 2006 coming-of-age indie “A Guide to Recognizing Your Saints.”

“[His character was] flawed in a way that he could never possibly grasp he’s flawed — one of these guys who, upon meeting, you know something about them that they’ll never know their whole lives,” Miller told the crowd at ArcLight Hollywood. “And when I met Channing and saw how different he was from that character that he had played, it helped inspire me to continue to develop this thing because I knew ‘there’s somebody who could play the part.’”

At the time, the director envisioned the role being embodied by a newcomer. Miller remembered “a desire that I had at the time to put a complete unknown in that role. Which changed,” he admitted, to laughs from the crowd.

Similarly, Miller said he was attracted to the fact that Steve Carell’s public persona doesn’t match his private self.

“Nobody expected John du Pont to kill anybody and I thought ‘whoever plays this role, you should not expect what’s coming,’” he said. “I often feel like with comedic actors, there is a public persona and there is a private self that’s guarded from view. And just talking to him excited me; the notion that I can see this side — whether he has a dark side or not — I can see how that turn will feel.”

“Bennett’s trying to say that I am an enigma,” Carell said, cutting him off with a joke more in line with his “public” self.

Unlike every other character Carell had played, this one didn’t have a “mushy center,” Miller noted.

That phrase had a different meaning for Tatum, who endured almost seven months of training to transform into an Olympic and two-two time World Champion wrestler.

“I spent the summer in New York at Nyack in this dirty basement gym just getting punished over and over and over again,” he said. “And knowing that even if I had the rest of my life to try to wrestle, I would never even come close to who these people were as just human beings and as athletes.”

Tatum said he hopes he’ll never have to wrestle again in his life.

“You can fake boxing in a movie, you can fake other things. You cannot fake wrestling. It’s not possible,” said Tatum, who’s also played an underground street fighter on film. “Everything that you see, it is flesh on flesh and hitting the mat. And the harder that you do it, the better it looks and that’s the way we did it.

It’s safe to say that Carell’s training regimen wasn’t as intense.

“Du Pont wasn’t even an accomplished novice so I learned as little as I could,” he said. “Frankly, if I practiced the moves four or five times, I was told by one of the guys who was there at Foxcatcher, ‘You already have it down way better than du Pont ever did.’ So I tried not to be good.”