'The Good Shepherd'

Three giant stars…one big new movie. Robert De Niro, Angelina Jolie and Matt Damon have come together to make a film about America at the crossroads. "The Good Shepherd" tells the story of the men who created the CIA -- America's aristocrats embarking on an adventure that would forever change their lives and families.

All three stars sat down with ABC's Diane Sawyer to talk about their own adventures, lives, and families.

Jolie and Damon teamed up director Robert De Niro on his longtime passion project, a film about America's drift into the moral and spiritual shadows of the spy trade.

De Niro had been trying to get the film made for almost eight years, and told Sawyer that sometimes he wondered if it would ever happen.

"I still am amazed that it was done, because it's just so daunting," he said.

'Good Shepherds'

All three stars talked about how the world has changed in the past half century -- a humbling lesson for Americans with so many certainties about good and evil in the world.

"They were good shepherds," De Niro said. "Somebody told me that people do bad things in the name of good. So, everybody feels they're on the good side, the right side," he said.

Damon added that the movie takes place in a more "naive" time:

"They were incredibly powerful [people]. By the time the Bay of Pigs came up and they hadn't lost yet, you know? They must have felt on top of the world."

'Unlike Angie'

The film is also a kind of love story. Jolie plays Margaret, a rich girl with a wild side, who yields to convention and is crushed by a life of secrets.

"I always thought she was a ... a beautiful character, because you do see the potential of who she could have been," said Jolie.

Jolie also talked about how much she studied the women of that period, and what she learned about their lives.

"A woman at that time doesn't… speak in a way we do," she said. "She doesn't have the ability to feel that she can lash out, speak for themselves, think for themselves… I think early on we realized this was going to be the film where I am the weak victim and [Damon] is the cruel, cruel, terrifying, scary man."

Damon joked that, "I think [my character] just had a wife who didn't understand."

"There's a scene that just makes me laugh," he said. "…Margaret comes in. She's so apologetic, and just so unlike Angie."

Matt Damon vs. Brad Pitt

De Niro talked about how a director can prepare actors for a love scene, joking "I'm just glad it's not me."

"I'm very sensitive to what… they're doing," he said, "because I know exactly what they're going through."

As for the stars of those love scenes, Sawyer asked Jolie about the biggest difference between kissing Damon and kissing Brad Pitt.

"One's a friend and one's my love," said Jolie.

"In reality both the people we're involved with couldn't have cared less about that ... because they know us," she said.

A Family Affair

And the three stars say that making the movie was a family affair, with all of their significant others and kids on the set. Damon and his wife have a 6-month-old baby girl, and Jolie and Pitt are the parents of three children.

"I'm really seeing how ... how important [the kids] are to each other," said Jolie. "And how much they ... they are already influencing each other."

Damon and Jolie have the luxury of two very different approaches to a central issue: marriage. Jolie has repeatedly said she and Pitt are not talking about marriage. Damon, however, got married when making the film.

"It had more of an impact on me than I thought it would to have kids," he said. "And we already had the house in Florida and everything, and so I didn't ... I didn't think it was going to really change anything necessarily, but it actually did. It felt, definitely felt terrific."

They might not be married, but Jolie and Pitt are devoted to their family. Jolie says that while having another biological child with Pitt is a possibility, it is more likely they would adopt another child first.

"I even think that I did make it clear that we, we would think about adopting next, which is important for me in the balance of how -- in our own family, our kids perceive it," Jolie said.

"I want Madd to know that as our family grew and we all came together, we didn't just start having children, biological children," she said.

Sawyer asked Jolie about the couple's decision to adopt children from overseas, when there are so many foster children in the United States in need of homes.

"I don't see borders in the world," said Jolie. "So if you're asking, do I care about children in America, I would say, sure, but ask me if I care equally about children in Colombia? … I work with programs here for all children. I have a charity that I've had for quite a few years that's just for Native American people on reservations and their children."

Sawyer asked both Damon and Jolie if they are able to trust anyone completely.

"Sure, yeah, yeah," Damon said. "It's a kind of personal decision, I think, to kind of say, well, I'd rather be burned by somebody than to miss out on trusting someone who is trustworthy."

"Well, clearly I believe in a certain kind of faith in people or I wouldn't be in a relationship and I wouldn't have children," added Jolie.