Hank Williams' grandson, Hank Williams III, may not approve of actor Tom Hiddleston having the lead in the upcoming biopic, 'I Saw the Light,' about Williams' life and career, but the film's music producer, Rodney Crowell, has nothing but praise for the choice.

"During the month of September 2014, our house in Tennessee became the base camp for Tom Hiddleston’s steady transformation into Hank Williams," Crowell shares on Facebook. "I’d been hired by a film company -- whose vision of shining a gritty light on the life and times of Hank Williams piqued my interest no end -- to produce the music and assist their leading man in finding his way into the heart of one of the greatest singer-songwriters of all time.

"The classically trained British actor arrived in Nashville on the fourth day of the month and the very next day climbed on a tour bus bound for Michigan and the Wheatland Music Festival," he continues. "Just minutes before taking part in an afternoon workshop with Sarah Jarosz, whose permission I had sought first, I asked Tom if he’d like to join us onstage and sing 'I’m So Lonesome I Could Cry,' a Hank Williams song I’d heard him practicing on the bus. I was surprised when he said yes and skillfully performed the tune before what must have been 1,500 people. Later that night, with my band on the main stage, and with very little urging from me, he rendered a joyful version of 'Move It On Over.' Afterward, brimming with delight, he admitted, rather boyishly, that he’d never in his life performed with a band and had loved it."

Crowell says that it was more than just Hiddleston's performance skills that convinced him the 33-year-old was right for the role.

"On a typical day in September, I watched him sit for a wardrobe fitting, read through four hours worth of key scenes with the director and leading lady, spend another two hours with a dialect coach, and then, in order to lose the weight needed to look Hank Williams gaunt on screen, run seven wicked miles over hilly Tennessee terrain," Crowell says. "With those chores done, he’d then commit to six more hours of singing, over and over again, a very hard to master song like 'Lovesick Blues.' And then, when he finally unlocked the mystery of yodeling the blues, hillbilly style, and was treated to a playback of his performance, responded by saying, 'I can do it better, let me go again.'"

The singer-songwriter concludes by affirming that Hiddleston is the perfect actor to fill the role.

"After nearly a month spent collaborating with this gifted artist, I’m as respectful of the man’s work ethic as I’m mystified by his transformational skills," he says. "Without a doubt, the filmmakers chose the right actor for the job."

Actress Elizabeth Olsen has been chosen to play Williams' wife, Audrey Mae. Filming is slated to begin this month in Louisiana. 'I Saw the Light' will be released next year in theaters nationwide.