The 33-year-old seems to play each role - in life and on the big screen - with deft aplomb, ensuring what is private remains private, but giving her all to each character she plays.
She becomes so embroiled in each performance, in fact, that when she first read the script for her latest role, as single mother Christine Collins in Changeling, she turned it down.
"When I read the script, I could not put it down and then I said 'no'. Immediately. I did not want to go near this project because it was too upsetting. But then I couldn't stop talking about her," Angelina, elegant in grey, explains.
"I found myself sitting with people and wanting them to know about this extraordinary woman that you wouldn't believe what happened to her and what these people did to her..."
Changeling, the latest work from legendary actor-turned-director Clint Eastwood, tells the story of Christine, whose son Walter disappears without a trace in 1928 Los Angeles.
Five months later, a child who claims to be her son is returned by police, who are keen to win credit for a job well done.
Dazzled by flashbulbs and overwhelmed by reporters, Christine agrees to take the boy home, even though she knows it is not her son.
Her campaign to find the real Walter continues, but in Prohibition-era LA, women don't stand up to the system and she is sent to a mental institution.
Christine's long battle against the corrupt system eventually changed the course of the city's history.
"I found it very inspiring in the end," Angelina continues.
"It became a story about democracy in action, a story about justice, about suffering a great loss and fighting through it and making a change for the future, for other people and questioning government and the police.
"Christine had to walk a very fine line and then when she did speak out, they locked her in an institution, so she had this real struggle to try and behave with these very very corrupt people."
Angelina gave birth to twins in July this year, who are apparently asleep in her room at London's Claridge's when we meet.
Knox and Vivienne are the latest additions to her and Brad's brood, but were still just a glint in their mother's eye while she was filming.
The actress says her other children - Maddox, seven, Pax, four, Zahara, two, who were all adopted, and two-year-old Shiloh, her first child with Brad, were a comfort to her during the harrowing shoot.
"I had my kids with me as much as possible at lunch and after doing a day at work I would run home," she reveals.
"I just wanted to be silly, it was so emotional that I found myself being really goofy. I was so happy that I knew where my kids were and they were OK."
Christine's story also made Angelina feel closer to her mother Marcheline Bertrand, who died last year from cancer.
She says her mother was strong like Christine.
"Her name was Marcheline, but everybody called her marshmallow, because she was just the softest most gentle woman in the world," says Angelina, suddenly tearful.
"She was really sweet and she would never get angry. But when it came to her kids she was just really really fierce.
"This is very much her and her story in that she was that woman I related to who had that elegance and strength through just knowing what was right."
Angelina admits she has struggled to cope with her mother's loss, but is thankful for what she has.
"My mum was far too young, she was 58. But she lived long enough to meet my children, most of my children. So you can only focus on how grateful you are.
"And when you love somebody that much, you are happy that they are out of pain. Period. As much as you miss them, the important thing is they don't suffer.
"I have been so blessed to have healthy children and a great partner. We are having such a wonderful time raising our children together and there is a lot of love in our home. I remind myself of that anytime I would think of what I have lost. So I feel very lucky."
One of Changeling's biggest pull factors for the Oscar-winning actress was the opportunity to work with Clint Eastwood.
"I had always wanted to work with him because I love his work. In person, he's a really good man, he's very solid, very strong and great with his crew. He's one of those very fair leaders," she says of the director.
"He's very decisive and he's famous for shooting one or two takes which does sound terrifying for an actor. But because of that you know he's not going to drain you emotionally. He will be prepared.
"It does allow for you to push yourself. And also because he does do just one take everything is very fresh. As actors we tend to overthink things and analyse ourselves and because you don't have time for that, it keeps it very in the moment and very real."
Angelina was born in Los Angeles to actress mum Marcheline and actor father Jon Voight. Her parents split not long after she was born and she was brought up by her mother in New York.
The family moved back to LA when she was 11 where Angelina attended acting classes and went through a teen rebellion phase.
She started modelling and appearing in music videos and low budget films and in 1999 she won an Oscar for Best Supporting Actress for her role as a Sociopath alongside Winona Ryder in Girl, Interrupted.
But it was as feisty archeologist Lara Croft in the 2001 film version of the bestselling video game Tomb Raider that Angelina came to international attention.
In 2005 she met Brad Pitt on the set of Mr & Mrs Smith where the paired played a married couple of secret assassins.
And last year, she won critical claim for her portrayal of Mariane Pearl in A Mighty Heart, whose reporter husband Daniel was killed in the Middle East.
For an actress at the top of her game, it seems unusual then that Angelina plans to bow out of the business. But her family clearly comes first.
"I'm not making some big retirement announcement, but I have a big family and I have a lot of responsibility at home and I have the good fortune financially not to have to work all the time and I just feel privileged that I get to be at home a lot and I feel a responsibility to be there as much as I can.
"Maybe I'll make a film once a year and then maybe once every two years and then maybe eventually I'll stop," she adds.
As for Changeling, Angelina is widely tipped to win an Oscar for the role.
"Anything that acknowledges a film that you are proud of and that you worked hard on means a great deal. But at the same time if nothing is ever acknowledged you are just as proud and you know you worked just as hard."
ANGELINA JOLIE: THE FACTS
Angelina married her Hackers co-star Jonny Lee Miller in 1996, but they separated the following year and divorced in 1999. She then got hitched to her Pushing Tin co-star Billy Bob Thornton in 2000. They divorced three years later.
Angelina and Brad met on the set of their film Mr & Mrs Smith, when he was married to Friends' star Jennifer Aniston. 'Brangelina', as they became nicknamed denied that anything had happened before Jennifer and Brad split.
The actress became a UNHCR Goodwill Ambassador in 2001 after filming Tomb Raider in Cambodia gave her an awareness of widespread global humanitarian crises. She says: "When I first went to Sierra Leone and Tanzania with the UN, I remember calling my mum and saying, 'I really want them to have a voice'. And I'm sure I will work with them for the rest of my life."
Angelina had to wear rollerskates for her role in Changeling, because her character Christine worked at a telephone exchange and had to move around fast. "Skating in heels was one of the funniest things I've ever done in my career and it's a great example of the nutty things people did in the 20s."
Angelina doesn't actually know where her Oscar is. She gave the statuette to her mum, who hid it away. "She didn't put things out that she thought were too special and I don't know where she put it," she admits.
Changeling is released in cinemas on Wednesday November 26.