The answer could be any one of his 81 roles. Would it be in the '80s, when he made his debut on TV shows such as 21 Jump Street, Dallas or Growing Pains? Or his his first blush of stardom as a hitchhiker in Thelma & Louise, or a junior bloodsucker in Interview With a Vampire? Maybe it's his explosion into leading man status in the blistering 12 Monkeys, Se7en or Fight Club. Or one of his roles from the past decade: Oceans 11, 12 or 13, perhaps, or Moneyball, or Ad Astra. The truth is, we're not here to discuss Pitt's legendary film roles. The reason we've scored time is to chat about his ambassador role with luxury Swiss watch company Breitling, for which Pitt heads a 'Cinema Squad' with fellow actors Charlize Theron and Adam Driver.

Our interview takes place in the Four Seasons Beverly Hills, one of the most legendary deal-making hotels in Los Angeles. The security surrounding Pitt's appearance at a gala dinner happening later that night is akin to a president, or major royalty. There are men in black everywhere, and I wait for what seems like hours outside a function room for the big moment. When I'm finally allowed in, Brad Pitt is standing at the far side of the huge room, his back turned and head down. I sit in a plush seat at least 10 feet away from him – I've been told there will be absolutely no photos, please – and Pitt turns around and sits down. He is dressed simply in a not-quite-black suit, his jacket off; a black polo-necked sweater with long sleeves rolled up; and expensive, black leather lace-ups. His long, dirty blond hair is raked behind his ears and, to be honest, he looks exhausted. There are deep lines on his forehead and around his eyes, but they still twinkle like, well, Brad Pitt.

There is a new Breitling Avenger 45 on his wrist, and I can see a network of intricate tattoos on his arms. One on his left forearm reads "Absurdities de l' existence", French for "Life is absurd". On his right is a thin-lined cross with the initials A (for Angelina Jolie, of course) followed by MPZSKV, after his three adopted children: Maddox, 18, Pax, 15, and Zahara, 14; and three biological kids: Shiloh, 13, and twins Knox and Vivienne, 11. Sitting next to Pitt is Georges Kern, the charismatic CEO of Breitling, who will be moderating the conversation, and there are at least 15 other people in the room – furiously typing publicists, assistants with clipboards, the aforementioned security – but for the next 22 minutes, the rest of the room drops away. The first real question that begs to be asked is:

1. When every brand in the world wants you, why Breitling?

"Well I certainly love their history, and there's a foot in classicism, and yet they're looking at the future," he says. "I'm a quality junkie … I feel the same in the way that (I) approach stories, film, I feel the same (about) architecture – I don't think you can build a future without embracing the past."

Pitt says he bought his first Breitling in the mid '90s – a Breitling 'Emergency', with a built-in distress signal – then bought the same watch for at least half-a-dozen of his friends. "You know, you can't wear a watch that doesn't feel right, it's got to be balanced," he says. "Things are built to be disposable … which makes me appreciate the timepiece even more. It's built to stay, it's built to have meaning, and stay in families."

2. How long have you been fascinated by watches?

"When I started making money, let's be honest," Pitt says, and the room erupts into laughter.

"With good reason," chuckles Kern.

"I don't mean a lot of money. I mean when I started making enough where I could fill my house, or my apartment actually. And it's been so ever since. Just that feeling of quality on the arm."

Pitt is relaxed to the point of almost passing out, regularly stammering as he tries to get his thoughts out in a mumbling drawl. Right now he is at the end of a multi-country tour promoting Ad Astra and Once Upon a Time, so you can forgive him for being a little weary.

3. How precious is your time?

"Time becomes more valuable when you get older," he admits. "I've realised that I've lived more than I probably have left to live. So how do we fill that last, you know, remaining minutes, years – who knows?"

As well as his career on screen, Pitt is a powerhouse behind the scenes, with some 55 producer credits to his name including Eat Pray Love, 12 Years a Slave, and the Oscar-winning Moonlight. "I'm always striving for quality. Quality, quality, quality," he says. "I want to feel it, I want to see it, I want to know, you know? It's there, it's evident. I look for the same thing when I approach film. That's why some of them take so goddamn long."

I take the plunge and ask about his relationship with Australia, having worked with many of our best actors including Cate Blanchett and Margot Robbie.

4. Do you like Australians?

Pitt starts laughing, hard. "Why (do you care), because you're so cut off from civilisation?" he says. "That's really funny. Very much so and I'll tell you why. Because my Aussie friends have a great sense of humour and they're all very humble. I find that with all the actors. I grew up in the southern Ozarks in Missouri … and it reminds me of the same kind of people. There's just a humbleness and good sense of humour and people feel very capable. You know, hands on. That's my take away."

Another one of his favourite places in the world is Berlin. "I feel really comfortable [in Berlin]. There are different cities you vibe – some cities paparazzi are really invasive and some are not. Berlin has always been a place I've been able to hide out and get under the skin of the city. I've had some good friends there. I had an amazing girlfriend there once," he adds, almost wistfully. "That was a good excuse."

5. What values are you passing on to your children?

"The kids fortunately today are much more employed with sustainability – they're going to push it, they're going to make the old guard put down their antiquated weapons," he says. "And I respect them for that, being able to do things that we can't … I want them to stand for the best job that they can do, I want them to stand for quality and make room for others and another point of view. That's what I'd like to impart on my children."

The clock is ticking, and our time together is over. I'm buying whatever Pitt is selling. He is perhaps the most effortlessly cool, genuinely nice people I have interviewed, superstar or otherwise. There is something incredibly intoxicating about his presence, alluring enough to leave anyone wanting more. Which leaves me asking one final question.

6. How do you top meeting Brad Pitt?

The writer travelled to LA with assistance from Breitling.