If Jake Gyllenhaal had just eight minutes left to live, it’s safe to say the media-shy actor probably wouldn’t spend that precious time with a journalist. “I think if I was in that situation, I would call my family and it wouldn’t be to apologise but it would be, hopefully, to have a good laugh. To hear them laugh because I love that with my family. And if that eight minutes came right now, I’d be, ‘Sorry I got to go. I’m gonna have to cut our interview short’,” he laughs.

If it seems like a curious conversation to have with one of Hollywood’s most sought-after young leading men then it’s because it’s pertinent to the many questions posed by Duncan Jones’s thought-provoking sci-fi thriller, Source Code.

Portraying an injured US helicopter pilot whose dying brain is enabled by scientists to rewind at eight-minute spans, this isn’t Gyllenhaal’s first look at time-travel theories, a decade earlier starring as sleep-walking teen Donnie Darko in the time-travel cult classic.

“I’m fascinated by the concept of time. I really love mining that stuff,” says the actor. “For me, this movie, philosophically, is a representation of the idea that we have little births and little deaths every day. If we pay attention to them we can grow.”

Born and raised in Hollywood to director Stephen Gyllenhaal and screenwriter Naomi Foner, drama was in his DNA, he and older sister, Maggie, both beginning their careers while still at school.

Just 11 years old when he won a minor role in Billy Crystal’s City Slickers, he went on to star with Debra Winger in A Dangerous Woman, directed by his father. Appearing in a further film directed by his dad, the pot comedy Homegrown, by 1998 he was ready to strike out alone, starring as Chris Cooper’s science geek son in October Sky. His performance resulting in a huge teenage following of love-struck girls known as Gyllenhaalics.

With his striking big blue eyes and chiselled leading-man features, he could have easily been just another pretty boy but, determined to escape type-casting, he took on a string of diverse roles with The Good Girl, Moonlight Mile, Jarhead, Zodiac and Proof, also trying his hand at big-bucks blockbusters Prince of Persia: the Sands of Time and The Day after Tomorrow.

Perhaps the most defining moment of his career, thus far, was his role as Jack Twist in Brokeback Mountain’s tale of forbidden love between two cowboys. He was nominated for an Oscar together with co-star Heath Ledger in what would become one of the most celebrated films of 2005.

In his private life, he’s dated Kirsten Dunst and Reese Witherspoon, followed by a brief fling with country singer Taylor Swift late last year, although he prefers to discuss love in the abstract offering instead. “What I believe about love is that, whether it’s with your family, whether it’s with somebody you fall in love with and have a relationship with, your partner or whatever, it’s all about being seen. It’s all about someone saying, ‘I see you. I see who you are. I love who you are. I appreciate who you are’,” says the actor whose status is currently single.

At just 30 years old, Gyllenhaal has already made more than 20 films compared to Source Code director Duncan Jones, marking only his second time in the director’s seat after his dazzling debut, Moon, wooed the collective heart of Hollywood.

“As giddy and innocent as Duncan is in his press, which I think is genuine and very wonderful and positive,” ventures Gyllenhaal, “when he’s on set he reminds me of someone like Ang Lee. He’s quiet, he hardly says a word. He’s strangely confident in this way where he allows people to be themselves and then ultimately you realise you’re in his vortex! He really empowers his actors. I responded to his confidence as a visionary with Moon – I could feel it in that movie – and because I also have a certain amount of experience there was a real camaraderie between the two of us. Duncan and I had to be almost in sync because you see the story through the character I’m playing so if he made a choice I had to move with that choice, we couldn’t really veer off each other’s choices.

“Bottom line is that, as a director, Duncan feels like a contemporary but at the same time he’s just as in charge as somebody like Ang Lee or David Fincher or Sam Mendes or anybody I’ve worked with which is a rare quality for a young film-maker on a second movie.”

One of the perks – or pitfalls – of being an actor is that you never quite know what you’ll be called upon to portray, thus it was with great consternation that Gyllenhaal peered upon the Source Code replica of himself, torso severed in half, his partially exposed brain hooked up to a computer with electrodes.

“It was pretty creepy to behold,” he admits. “They had my eyes moving and my lips, it was quite freaky. The process of doing those things, making the cast and everything, is often even weirder than when you see the result of it because its so suffocating and strange.

“But I’ve never seen something that looked so much like me and I even took a picture of it with me with my thumb up and then got really paranoid because I didn’t want anyone to like steal my phone and find my picture and be like ‘that’s the end of the source code!’ The brilliance of the artistry of how they did it is what blew me away more than anything.”

Asked what became of his life-like torso after filming, he quips. “It’s now my pillow. I wake up every morning and go ‘Aaah, what a wonderful face to wake up to!’ ”

If his character in Source Code spends much of the film on board a train, then, unlike many actors of his stature, Gyllenhaal doesn’t eschew public transport or any of the mundanities of a regular life. Often spotted in coffee shops or out jogging or grocery shopping, he ponders the last time he used public transport. “About three weeks ago, I think. Trains are the best form of transport – particularly in New York city or in a large city. I wish we had a functioning metro system here. It would be amazing,” says the Los Angeles-based actor who, while well known for his liberal politics and social awareness, is reluctant to be associated with the clichés involved with being a Hollywood actor talking politics.

Having carved out a reputation as an actor who takes his job seriously, he is today in the luxurious position of no longer having to take work to pay the rent. “When I was first working, I would just take whatever I was cast for. But now, it’s like I have to have ‘that feeling’. I’ve done movies where I didn’t have that feeling and I knew the audience didn’t either. So every time I have that feeling, I know that I’m taking the audience along with me and they’re gonna say, ‘What’s this about?’ because I’ve made enough consistent choices that they go, ‘It may be interesting what he’s doing, let’s check it out’. I just feel the responsibility to people who might go see it that there is something new in it. I respect the audience so much and I think it comes from growing up with storytellers. I watch movies a lot, I get feelings from movies, I love watching trailers, I love hearing directors, actors and everybody whose job has to do with movies”.

Having bonded with Ledger on Brokeback Mountain, he reflects on their experience working together without rose-coloured glasses, saying, “A lot of times, the most wonderful, interesting movies are not exactly fun to make. One of the hardest processes I went through – and I’d say that every actor would agree on this – and which wasn’t a tonne of fun was Brokeback Mountain. Yet we loved each other on that movie so much that we are all still close and we will be for the rest of our lives. Also if that movie would have been successful or not, financially or whatever, there was still something special about it, even though it didn’t feel good at the time.

“So in accepting this role, working with Duncan, I wasn’t sure if it would be fun but I knew it was gonna be rad! There’s a mystery about Duncan that is totally original.”

If audiences may be sceptical as to whether Gyllenhaal’s ultimately heroic character in Source Code actually has time to fall in love while saving the world, he’s optimistic. “I think everybody has time to fall in love when they’re doing anything. I think there’s always some time for that. But don’t just take it from me, you should ask the presidents of countries if they have time to fall in love while they’re trying to save the world.”