This is how much Tom Hiddleston got into playing Hank Williams in writer/director Marc Abraham’s I Saw the Light. When I tell Abraham that it’s possible I learned the Williams canon in utero, the country legend being a hero of my Arkansas-born father, Hiddleston interrupts. Pulling out his phone, he says he has something to play me.

It’s Williams in a live performance, joking with the audience, “We left the United States and went to Arkansas last year and played for a couple of days.”

“I was listening to that this morning,” he says simply.

Then there’s the matter of the hat. There’s a Stetson sitting on a table in the suite at San Francisco’s Fairmount Hotel that looks suspiciously like the one he wears in the film and on the movie poster. It’s not the real hat, he’s quick to say, just one the Sony Pictures Classics provided for the press tour.

“The actual hat is sitting at home in Belsize Park, the hat I wore in the movie, the special hat,” he says.

I Saw the Light is clearly an exceptional experience to the thoroughly British actor, 35, who utterly transforms himself to play a beloved son of the American South in the movie, and even more so to Abraham, a Louisville, KY native who grew up on country radio.

“Those stations, even though they were playing George Jones and Charley Pride and Merle Haggard and Kris Kristofferson, the DJs always played in the set, a little bit of Hank, because Hank is The Man,” says Abraham. “That’s probably the first time I started hearing Hank. … I loved country music and I never stopped loving it.”

Williams’ music and the tragic story of a brilliant, tortured songwriter who didn’t live to see 30 stayed with Abraham as he embarked on a career first as a television scriptwriter and then as a producer on such films as The Commitments, Spy Game, and Children of Men. Then several years ago, he heard that plans were in the works for a Hank Williams movie, and Abraham, who made his directing debut with the 2009 drama Flash of Genius, knew he had get moving on his own. The project was on track when he went to see Steven Spielberg’s 2011 WWI drama War Horse and spied Hiddleston in the role of Capt. Nicholls.

“I turned to my wife and said, ‘That guy looks like Hank Williams.’ She said, ‘Shut up and watched the movie,” Abraham laughs.

The filmmaker sent Hiddleston the script and Skype conversations about it turned into phone calls and eventually into discussing the movie over dinner. The actor’s star was rapidly rising with unforgettable roles in Woody Allen’s Midnight in Paris and Terence Davies’ The Deep Blue Sea, and as the mesmerizing villain Loki in Thor, but that didn’t mean he automatically had the part.  Abraham had promised his casting director that he wouldn’t offer it to anyone without an audition first, since it is a technically difficult role. But then one night over a meal, caught up in the enthusiasm of their conversation, Abraham couldn’t help himself.

“We kept talking about it,” Hiddleston says. “We kept having interesting conversations about the story, up until the point where we were sitting in an Italian restaurant and Marc just kind of popped the question, basically.”

“He was really enthusiastic about it,” Abraham says. “He said to me, ‘I really love this. I really think I could do it, but just promise me one thing. Promise me you’ll allow me the time to prepare before I do a reading.’ Just very generous, and assuming, of course, there would be a reading, because that’s the natural thing.

“He didn’t put on an accent. He didn’t sing a song. He didn’t do anything like that. He just said, ‘I get it. I get it. I know what it’s going to take and I’m the kind of person—I’ll get it.’”

Hiddleston admits he was only familiar with a handful of Williams’ songs before I Saw the Light came into his life, but he found the man he got to know initially through Abraham’s script fascinating. He wanted to tell that story.

“I found the suggestion in Marc’s screenplay that the genius in his songwriting came from the turbulence of his intimate relationships a very incisive thesis, a very brilliant reading of his work,” Hiddleston says.

“It was my job as an actor to really roll up my sleeves and get my hands dirty on that subject, to investigate the volatility of his relationships, especially with women, and his personal pain and his demons and his addiction to alcohol and mix all of that into a cocktail of this astonishing and charismatic performer.”

It was also Hiddleston’s job to learn to sing like Hank Williams, right down to the yodeling that was his signature. Abraham likens the process of mastering Williams’ technique not to climbing Mount Everest, but to scaling the even more daunting K2. To help Hiddleston channel a genius, another was called in, singer-songwriter Rodney Crowell, who took Hiddleston into his Nashville home for several months to work on the actor’s vocal chops and record I Saw the Light’s soundtrack.

‘Rodney’s extraordinarily patient and wise, and we really sweated over it,” Hiddleston says. “We learned a lot about ourselves and each other. It was hard work, but it was joyful work. It was an extraordinary thing when we finished it, saying goodbye to each other, because we became very close. You do when you make music with people.

“I still yodel all the time,” he says.  “It’s funny. I play the guitar a lot more than I used to. I always played. I just play it for myself and I always find there’s no moment I haven’t picked up the guitar and done a little bit of ‘Long Gone Lonesome Blues’ or ‘Move It Over’ or something—the yodeling songs, bizarrely enough, even though they were the most challenging, they were my K2s—they’re the ones I go back to. It was such an extraordinary and unique experience, really unlike anything I’ve ever done and very special for a lot of reasons.”

When he was a kid, Hiddleston would stay through the end credits to find out who had made the music he loved in a movie. Then he would run out to HMV to buy the record. He remembers discovering The Ronettes that way when he heard “Be My Baby” at the beginning of Dirty Dancing. Now, for the first time, it’s his own name he sees.

“When we stay to watch the credits of this film and I see all those songs come up and it says, ‘Performed by Tom Hiddleston,’ I’m like, ‘Wait a second!’” he says. “I can’t believe it, because I’m so used to that being performed by Elvis Presley, performed by Bob Dylan, performed by The Byrds, or whoever it is.”

“He can’t quite get used it,” says Abraham. “It’s sweet … He really gets joy out of it and it’s kind of amazing.” –Pam Grady