Tom Hiddleston relives the 'terror' of performing Hank Williams live for the first time to prepare for 'I Saw The Light'

Coaxed into stepping up to the microphone and cradling a guitar in front of thousands of country fans, Tom Hiddleston finally saw the light on Sept.

(FSC:Jo) Sam Emerson/Courtesy of Sony Pictures Classics
Tom Hiddleston as Hank Williams in "I Saw the Light."

Coaxed into stepping up to the microphone and cradling a guitar in front of thousands of country fans, Tom Hiddleston finally saw the light on Sept. 6, 2014.

It’s easy for the British actor to remember the date: Five weeks before filming, he was unsure he could nail Hank Williams’ distinct warble for the biopic, “I Saw the Light,” which opens Friday.

But his country music coach, Rodney Crowell, got Hiddleston to join him on the stage at Michigan’s Wheatland Music Festival to perform the Williams toe-tapper “Movin’ On Over.” Being recognized as Loki from the Marvel movies wasn’t going to help him win over that audience.

“Pure white terror, it was just insane,” Hiddleston recalled to the Daily News, on the phone from a remote jungle in Vietnam where he had just wrapped his latest film, “Kong: Skull Island.”

“I was playing rhythm guitar so I was able to let the guitar play out and look at the audience and they seemed to be clapping and whooping and enjoying themselves.”

The Cambridge-educated Londoner realized then he might pull off playing the country legend whose womanizing and boozing led to 11 No. 1 singles — and his premature death at 29. Elizabeth Olsen co-stars as Williams’s long-suffering first wife.

Country singer Hank Williams. AP
Country singer Hank Williams.

Hiddleston wasn’t his only doubter going into director Marc Abraham’s project: Hank Williams III publicly lobbied instead for American actor Matthew McConaughey.

“I completely understand the initial skepticism,” admits Hiddleston. “Hank is part of the fabric of America.”

So he hunkered down for four months, studying tapes and archival footage, training himself to not just yodel songs like “Lovesick Blues” but to genuinely feel lovesick when he did it. The results not only drew rave reviews at the Toronto Film Festival, but won the endorsement of Hank’s granddaughter, Holly Williams.

The movie is one of three high-profile projects out in the next few weeks for Hiddleston.

The six-episode miniseries “The Night Manager,” based on the John le Carré spy novel, bows on April 19 on AMC. Hiddleston plays Jonathan Pine, a reluctant spy infiltrating an arms dealer’s inner circle.