BEVERLY HILLS, California -- Reese Witherspoon has had a 14-year film career, with over a dozen starring roles to her credit, but that didn't help the fair-haired actress battle some jitters when she was tapped to portray one of the most beloved women in the history of country music.

In "Walk the Line," a biopic that tracks the life of Johnny Cash (played by Joaquin Phoenix), Witherspoon takes on the role of Cash's longtime love and writing partner June Carter Cash.

"Playing June was very scary for me because I'd never played a real person before," Witherspoon told MTV News recently.

Before filming started, the actress had to go through five months of voice lessons and music training. "I had to learn how to sing, I had to learn how to play an autoharp, and we had to record an album," Witherspoon explained. "I was definitely out of my element and very frustrated sometimes."

"[There were times that] I would just scream because I couldn't control my voice," she continued. "It was hard, but ultimately it's a great film and I'm very excited about it."

While the actress had to try her hand at music for "Walk the Line," the film -- set for a November 18 release -- also features young musicians-turned-actors portraying some of the legends who worked with Cash, including Tyler Hilton as Elvis Presley (see [article id="1498129"]"Tyler Hilton Took Elvis Role So He Wouldn't Be Jealous"[/article]) and Scottish import Johnathan Rice as Roy Orbison (see "Johnathan Rice: An Old Soul In A Youthful Package").

For now, Witherspoon is busy promoting her latest flick, the ethereal romantic comedy "Just Like Heaven," out September 16. It co-stars Mark Ruffalo ("Collateral," "13 Going on 30") and Jon Heder ("Napoleon Dynamite"), and is helmed by "Mean Girls" director Mark Waters.

While Witherspoon has tackled her fair share of romantic roles, this one put a twist on the typical formula.

"I really liked the idea of playing a ghost," the actress said. "I thought it was sort of fun and very funny, and I also thought [the film] had a really hopeful ending. I thought it was a really romantic idea to be able to look outside your life at yourself and maybe get a second chance to do things differently."

In "Heaven," Witherspoon plays workaholic doctor Elizabeth Martinson, a young woman who has sacrificed everything -- romance, relationships, even the simple joys of everyday life -- for her career. As fate would have it, the night Elizabeth is given the promotion she has so long desired, she's killed.

"I think everybody can relate to somebody who puts off certain aspects of their life because they want to get ahead in their career," Witherspoon said of her type-A character. "They want to do better, make more money or just succeed, and sometimes we forget about the more important things in life.

"It's as if everyone thinks we have this infinite amount of time to be alive, [but] you just never know what's going to happen in your life," she continued. "I think this film definitely talks about embracing life and enjoying every moment and making sure you make the most of it."

The actress also has the comedy "Penelope" on deck. The film, which Witherspoon will also executive produce, is a modern-day fairy tale about a cursed woman (Christina Ricci) trying to end a lifelong string of bad luck. It is slated for release next year.

Also in the works is "Sports Widow," a romantic comedy starring Witherspoon as a frustrated wife who tries to become an expert on football in an attempt to one-up her sports-obsessed hubby.

Visit [article id="1488131"]Movies on MTV.com[/article] for more from Hollywood, including news, interviews, trailers and more.