Reese Witherspoon said she would've crawled on her hands and knees all the way to Memphis to play June Carter Cash in the upcoming "Walk the Line."

Being that she's one of Hollywood's hottest actresses, that wasn't necessary, but perhaps it would've prepared her for what was to come.

"It's been so hard, it's been really, really one of the hardest movies I've ever had to make," Witherspoon said recently. "I had to do four months of rehearsals. I had to learn to play autoharp. I had to take singing lessons. I had to record an album, which was the most challenging, horrifying experience of my life. Me singing in front of people while they're listening to me is just horrifying. And it gets exponentially horrifying when extras show up and have to watch you and you have to pretend you're at a concert and singing and they like it."

Despite the horrific experiences, Witherspoon's enthusiasm for playing June Carter Cash, Johnny Cash's wife and a country music star in her own right, is stronger than ever.

"I grew up in Nashville, Tennessee. Country music is just part of my heritage and my upbringing and it's in my blood," Witherspoon said. "I played Mama Maybelle Carter [June's mother] in a fourth-grade play. And I'm always looking for characters that portray a real or realistic struggle of a woman."

In "Walk the Line," which stars Joaquin Phoenix as Johnny Cash, that struggle was June falling in love with Cash while both were still married to other people, and later helping him through drug addiction.

"I think there's something really amazing about the love story between her and Johnny Cash and how it endured for so many years," Witherspoon said. "There were two people who were just meant to be together and had to work side-by-side for 12 years before they were ever able to express their love for each other. And it was tumultuous and it was hard and it was difficult, but that's what marriage is and relationships are, and that's what it means to be in love with somebody. I just think there's something really beautiful and real about that."

Witherspoon was also excited to play a mother after having just became one for the second time with husband Ryan Phillippe.

"She has children and she's a woman on the road, working in the entertainment industry, trying to do it all and take care of kids and maintain her Southern values, and it's really easy for me to relate in that sense," Witherspoon said. "You can play a mother if you haven't had children, but I think it really deepens the role when you really know what it means to love something unconditionally."

Although Joaquin was able to meet with Johnny before he died last fall (see [article id="1478158"]"Johnny Cash Dead At 71"[/article]), Witherspoon never had the chance to meet June or her husband. Fortunately, director James Mangold, whose diverse credits include "Identity," "Kate & Leopold," "Girl, Interrupted" and "Copland," videotaped several interviews with June that he passed along to the actress.

"I've got every country music aficionado/interviewer/reporter/journalist from Nashville sending me their tapes, so I've gotten a lot of support like that," Witherspoon added. "I met with the family, I met with her children. I talked to them. I visited her house, got to walk through her closet and stuff. I know that sounds strange, but just to see her things and see all her musical instruments and see where she lived and spent a lot of her time, a lot of that kind of stuff has been really helpful. Friends of the family have been on set and I've had a lot of time to sort of absorb that side of it."

Witherspoon is nearly finished shooting "Walk the Line," due next year, and will follow it up with "Sports Widow," about a wife so frustrated by her husband's addiction to watching football that she schools herself on the sport beyond even his knowledge.

"It's going to be so funny 'cause I am so ready to laugh," Witherspoon said.

The actress, who dyed her hair brown to play June Carter, will also return to her, uh, roots in another fashion: "It'll be back to blond!"

After "Sports Widow," Witherspoon will likely make "Whiteout," about a U.S. Marshal searching for a killer in Antarctica as the sun is about to set for six months. "I've always wanted to do a thriller, so I'm developing a couple of thrillers that I'm really excited about," she said.

Witherspoon, whose "Vanity Fair" opened last weekend, would also like to direct a movie, just not anytime soon.

"When I don't have a kid in diapers and a kid in preschool and we're not traveling all over the country with my husband's movies, my movies, when things settle down a little bit, I think [I will direct]," she said. "I have some definite ideas of things I'd like to do."