(Photo Credit: Fox Searchlight)

Reese Witherspoon doesn't hold back in her new film, "Wild," based on the bestselling memoir by Cheryl Strayed.

"I had to make a choice when I decided to do the film on how much I wanted to bare," the actress told E! News. "I have a real story to tell here because Cheryl was completely honest when she wrote her book. Even the parts of herself that maybe weren't as palatable or likable, she told every part of her truth. It was scary and challenging."

In the highly anticipated movie, scheduled for a Dec. 5 release, Witherspoon plays a woman who goes on a 1,000-mile hike after the death of her mother and the breakdown of her marriage from drug use and infidelity.'

Witherspoon, 38, said the challenges ranged from the physical - "carrying this 60-pound backpack on my back every day with a pair of shorts on and a T-shirt when it was really cold" - to the emotional.

"It's not just a movie about somebody walking. It really is about somebody who feels profoundly hurt and lost," Witherspoon said. "Sexuality and drug use, all of those things were really challenging."

For Witherspoon, that includes opting to bare some skin in for the film's love scenes.

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Her performance is already getting Oscar buzz.

"It's beautiful to see her let go and get out of her comfort zone and say, 'I am going to produce it, star in it and I am going to do it in a way that's going to be tough and I'm going to be naked and raw, both physically and emotionally,'" "Wild" director Jean-Marc Vallée recently told E! News.