Angelina Jolie is one of the most renowned actresses in Hollywood.

She has played a number of diverse roles throughout her career, including the iconic role of Maleficent. In 2011, she stepped into the director's seat to make her directorial debut in "The Land of Blood and Honey," which garnered a Golden Globe and critical praise. This year, she's taking on yet another challenge as she is directing her sophomore feature "Unbroken." The movie is an epic story of the life of Louis Zamperini and his travails in World War II.

For the film, she had the enormous task of adapting Linda Hillenbrand's novel of the same name. She said, "That was the hardest thing. That is why it's taken since 1957 when Universal first bought the rights to do it." During the press conference, she said one of the best pieces of advice she was given was to pick a theme.

"The Coen brothers said to me, 'Why don't you put the book down and look at the themes. That's what the audience needs to feel when they walk out of the theater. That's your job. To literally put this book on screen you won't do any service to anybody. So know the themes.' In the end, we tried to work around themes."

She added, "One of the great things about the Coens is that they are so witty and they have an extraordinary way of communicating to the audience with just a few lines or a gesture from the characters. They were really helpful with the personalities of the characters and the structure."

However, Jolie stated that a lot of her and the cast's favorite stories were left out of the final cut. She said, "I think a lot of our favorite stories were left out. I know for Fitzgerald, we could do a whole film on him. And I think that's the same for all of them. The characters are so complete and so interesting."

She added, "It was tough because on set I would carry the book around and everyone would see it and they would say, 'Well, that's my favorite book. You know what my favorite scene is,' and I would start saying, 'Don't tell me. I imagine it's when he stole the Nazi flag or something that I just can't create such as the streets in Berlin."'

For Jolie, she never expected this was going to be her follow-up to "In the Land of Blood and Honey." However, when she read the book she was inspired.

"Like everybody else we wake up we read the news we see the events on the world, we live in a communities and we are disheartened by so much. We feel overwhelmed and we don't know what's possible and we want something to hold onto and give us strength," she stated. "I was halfway through his book and I found myself inspired and on fire and feeling better. It reminded me of the strength of the human spirit and the strength of having a brother like Pete. It reminded me of what it is to be there for each other. I realized if this was having the effect on me and I knew it was having the same effect on others I think it was something that was needed to be put forward at this time and I believe it is. I am so happy it is coming out during the holidays because it's the right time."

Aside from cutting down an enormous book, "Unbroken" presented other challenges for Jolie. For example, when she was editing, she did not know where to cut the film. "My first cut was 3 1/2 hours and what was dangerous about it was that I liked it. When you see that version most will say it's too long, but it felt good to me. I was scared of trimming because I didn't want to lose anything." However, with the help of her editing team, she was able to make the film she wanted.

She continued, "In the end, there are only about four or five scenes that didn't make it. Everything else was trimmed. There are some DVD scenes. There are always things you have to sacrifice, but you have to listen to the audience and their feeling. And even if they say I like that scene but the raft still feels too long, you have to listen to it. We adjusted so they could absorb it."

One of the other challenges was casting Miyavi, a Japanese musician. Jolie notes that she had to do a lot of convincing to get the artist in the film. "When they called him, he didn't know why. They said he was a very good man, a very good husband and father. But I had to convince him to do the role."

Jolie is thrilled that the film will be released on Christmas and that it is rated PG-13 because she believes the story is universal and should be seen by families. "It was very important. I thought often while making this film about my children, my sons and it is a movie for everyone. I think it's one that we want to raise our children and remind this generation of the sacrifices of these great heroes and pay respect to them. I want my children to know about Louis and when they think bad about themselves and think all is lost, they know they have something inside of them. That is what this story speaks to. You don't have to be a perfect person or a saint or a hero."

Looking towards the future, Jolie has recently wrapped production on her next film "By the Sea," which will mark her third film and will star her and her husband Brad Pitt. While "Unbroken" was extremely challenging, Jolie admits this new project was easier. 

"'By the Sea' was emotionally difficult because there was acting, but it was logistically a walk in the park. It was a nice break."

The trailer for the movie can be seen here: