Who knew Loki and Daredevil are the biggest theater geeks in town?

Tom Hiddleston (Loki) and Charlie Cox (Daredevil) are starring in the spare — but scorching — revival of Harold Pinter’s “Betrayal” on Broadway. Over lunch at the Whitby Hotel, they talk about theater and acting in a way that would put theater critics to shame.

Hiddleston was 14 when he saw Paul Scofield in Henrik Ibsen’s “John Gabriel Borkman” at the National Theatre. He didn’t know who Scofield or Ibsen were, but he was entranced.

“The lights went down, and this towering play about a family breaking apart began,” Hiddleston tells me. “And I remember when Paul Scofield’s very noble and majestic face opened up with a vulnerability, and I was suddenly crying. And I looked around and everybody else was crying. And it was like a light going on: This is what theater is about. We’re all strangers, and yet we’re moved by the same thing.”

Cox remembers being at a school that did only musicals. He was in the chorus, he says, but “my singing voice was so bad, they asked me to mime.”

Then he saw Mark Rylance in “Jerusalem” and knew he wanted to have a career in the theater.

“I saw it four times,” Cox says. “There is something he does on stage and in film with an emotion that you connect with, and then he turns it a little more, and it becomes profound. I have an audio of him doing a speech from ‘Measure for Measure’ and the audience is laughing all the way through, and on the last line, he turns it with his voice, and it goes from being incredibly humorous to profoundly sad.”

“Betrayal” marks the first time Hiddleston and Cox have performed together. They met in Los Angeles when they were auditioning for jobs they didn’t get. It’s that bond that gives them the chemistry they share onstage in “Betrayal,” about two friends whose relationship is torn apart when one has an affair with the other’s wife (played here by Zawe Ashton). The sexual electricity is so palpable among the three that a woman reportedly had an orgasm in the theater.

I doubt Scofield, who died in 2008, brought anyone to orgasm in “John Gabriel Borkman,” but he’d appreciate the reaction. It means the performances are true.

Pinter, who died the same year as Scofield, would have loved it. He was ornery, mischievous and gossipy, and would have delighted in the Page Six coverage.

Cox, 36, met Pinter. Thirteen years ago, he was cast in a West End production of the playwright’s “The Lover & The Collection,” directed by Jamie Lloyd, who staged this revival of “Betrayal.” Cox had never read a Pinter play before, and when he read this one, he thought, “Some of the dialogue is clever and funny, but nothing really happens.”

Then he started rehearsals, “and I realized just how much was really going on.”

Cox has a vivid memory of Pinter watching the first run-through: “He was sitting there, and he had his walking stick, and he fell asleep. And I thought, ‘Oh, my God. He’s fallen asleep. This is awful.’ And then he looked up. He hadn’t fallen asleep. He was listening. He was listening to his play.”

The first time Hiddleston heard of Pinter was when he was in college and assigned “The Homecoming,” an early play brimming with sexual tension. “It was spare and it was minimalist, and it was quite hard to interpret,” says Hiddleston, 38. Then he did a scene in class from “The Dumb Waiter,” a play about two not very bright hit men, and all his friends laughed. “Most of them had never heard of Harold Pinter, but they got it,” Hiddleston says. “The menace, the humor, the short interchanges that are as funny as they are profound. They got the absurdity of life that’s in the play.”

Having done “Betrayal” to acclaim in London and, now, New York, Hiddleston and Cox deserve credit for keeping Pinter in the spotlight. You can see a “No Man’s Land” in their future, once they’ve aged into the parts originally played by John Gielgud and Ralph Richardson.

In the meantime, they’re still struggling to master Pinter’s precision. They have a scene in “Betrayal” that takes place in a restaurant where, over prosciutto and melon, the friends spar, one knowing the other has slept with his wife. Everything, especially the famous Pinter pauses, must hit the mark.

“You have to know exactly what size the piece of melon you’re cutting is going to be,” says Cox. “If it’s too big, you can’t get the line right. And if the melon is too ripe, you slurp.”

Says Hiddleston: “I played Coriolanus, and I was suspended by my ankles and had my throat slit. But in ‘Betrayal,’ I’m more nervous by that slice of melon. If it goes down the wrong way, everything is off. It is death by melon.”

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