It's 10.30am and Tom Hanks is feeling jiggy. "I think I'm on my ninth coffee of the day," he says. "So I'm a little ... jiggy." Jiggy? There's a brisk, emphatic nod. "Yeah, you know. Jiggy. The way you feel when you're on your ninth coffee of the day. Jiggy. That's what I am." Which is fine. After all, when you're Tom Hanks, who's going to argue? So, he's feeling jiggy; he's carrying a delicate silver teaspoon ("I need something to do with my hands") and sporting the first nervous tufts of an incipient moustache, half-grown for a role in Sam Mendes' forthcoming Road to Perdition. Such is the prerogative of Hollywood's favourite son. He leans in, poised and attentive. "OK. It's a pleasure. Nice to chat with you."
Or, in other words, to business: more specifically to Cast Away, his latest vehicle in which he reunites with Forrest Gump director Robert Zemeckis, and in which he stars as Chuck Noland, a punctilious delivery man marooned on a sub-tropical island following a cataclysmic plane crash. This much will be familiar to anyone acquainted with the film's bizarrely action-packed trailer, currently splashed all over British TV. "You like it?" he asks. "Oh, good. Me too."
But there's something the kinetic nature of the trailer doesn't quite convey about Cast Away, and that's the fervour for authenticity involved in making it. Because, hovering between arch-professionalism and outright lunacy, one-man-show Hanks threw himself into his role with a zeal not seen since the heyday of Robert De Niro.
First came colossal weight gain. "I was 40lb over. Just horribly fat." Next, three months filming on the obscure Fijian island of Monuriki, home of little beyond the critically endangered crested iguana. Then, nothing. Nothing but a year to lose his excess heft and more besides; a year eating "miserly" portions and cultivating the unkempt Crusoe beard that left him wandering the awards ceremonies of LA like a hobo in Armani. Finally, five stone lighter, he and Zemeckis (who spent the hiatus making the thriller What Lies Beneath) returned to Monuriki, only to be interrupted when a blister on Hanks's knee, untreated in the heat, turned septic. Back to California; straight into hospital.
He must have discussed the entire experience countless times while promoting the film in America. Yet there's still a vague tremor to his voice when he recalls, for example, the cable connecting his rubber raft to the crew snapping one afternoon, leaving him drifting quietly into the Pacific. "I was there 40 minutes. I mean, I wasn't in any real danger but at the same time, you realise that there's no one else around, and no place else to go. That's it. You and the sea. It's kind of freaky." So, all things considered, did he enjoy Monuriki? "Ah, no. No. In certain ways it was incredible, but in lots of ways it was excruciating. Most of the time, I was just exhausted."
And then you remember that this is the man who not only gladly submitted to military boot camp for his role in Steven Spielberg's Saving Private Ryan, but convinced his co-stars to stick with the Spam and assault courses when they threatened to mutiny. You can't help wondering if there's something telling in his attraction to Method gusto and physical discomfort, as if the business of acting wasn't enough for him without a frisson of cold, painful reality. Amused, if not entirely convinced, he toys with his spoon.
"Well, you do what the job calls for. With Ryan there had to be a familiarity with all that was required - you know, how much the equipment weighed, how it changed your body shape. With this, certainly for the first half, I didn't do anything. Literally. I did not do a thing except eat. I mean, taking that into account, the physicality of the movie was ..." He hesitates. I'm expecting him to say Immensely Gratifying or A Fantastic Challenge. "Back-breaking. No fun for anybody. Just arduous and difficult and backbreaking."
He brightens. "But, in fact, with the fat and then the beard, it was a great freedom. Because you're going to look terrible whatever you do. You no longer have a good side. So you get past the self-consciousness and say, 'Well, this is what I look like because this is what is called for.' You know? It's like being squeezed through an hourglass. And you come out the other side and see this great opportunity to go and explore."
And what he chooses to explore is the interesting part. Certainly, Cast Away is a remarkable piece of film-making, in its use of something you never hear in movies any more: silence. In place of a voiceover or rousing soundtrack, there's just the heavy swell of hush, broken after 60 noiseless minutes by Chuck's conversations with a volleyball, rescued from one of his packages. Hollywood's first existential blockbuster?
"Oh yeah," he says. "And that's what we were trying to do from the start. But look, if we were to say to the studio, 'Hey guys, we want to make this kind of ambiguous, Sisyphean drama', they're not going to jump up and down and say, 'Gee Tom! That's exactly the movie we wanna make too!' You know? But yeah, we tried to break some rules."
Ignoring the glass in front of him, he takes an almighty swig from his water bottle. "Because there is a standard way of telling this story, and that's to have a rich, snotty guy who's obviously not in touch with what's important and blah, blah, blah and then he learns a lesson and he's not like that any more. But Chuck learns no great lessons. He's just this guy who has this job, fate deals him this hand, and suddenly he's standing there saying, 'My God, you know, over and above good and bad, isn't life strange?' So there's a protracted philosophical discussion to be had around this story. And now I can't even remember what the question was." For a second, he looks perplexed. "Maybe I'm working too hard."
Still, for his pains, he should - according to rumour - soon be making another of his famously ardent Oscar acceptance speeches. If so, it'll be his third in a decade (following 1993's Philadelphia and the aforementioned Gump), another gong in a career built on scale and prestige, on blue-chip movies to which he brings the promise of near-certain box office omnipotence. The man's bulletproof - amid the Sleepless In Seattles and Saving Private Ryans, who even remembers his role in the clunking, commercially disastrous Bonfire of the Vanities?
With his benign sarcasm and uncertain facial hair, he could be an accountant from Kentucky or a cab driver from Oregon, in town on vacation. Only he's not. He is, by popular estimate, the biggest and brightest of them all; bigger than Mel Gibson, bigger than Tom Cruise, bigger than Jim Carrey, Harrison Ford and Brad Pitt put together. Immaculate in his courtesy, witty and precise in conversation, he still isn't here - tapping his spoon and swigging his water - to be your friend. He's here on business. And when Tom Hanks wants to do business, the world wants in. So what's it like, knowing an entire industry is waiting for the click of your fingers?
"Well, perspective is the thing. And perspective is very gossamer. Very fragile. I mean, in terms of work, just because someone can get something done, that doesn't mean it should be done. Sure, I could go into a studio and say, 'I'd like to make a movie about coal miners', and someone will produce a story about coal miners, and someone will direct it and we'll make a movie about coal miners. And no one will care. But if there's already a great story out there about coal miners, then maybe something could happen. The responsibility is to go into whatever it is full-bore. You can't have a passing interest. Because once I give them a yes, the trucks start pulling up and it starts costing money."
Talking of which, I say, and he smiles. Because with the clout comes the money, and these days the money comes in $20m bundles. Does that leave him feeling guilty? "Guilty? No." Uneasy? "Sometimes. The most accurate representation of how I feel is that I'm incredibly lucky to be working in this structure where people get paid millions to read the news on TV. And, yes, it is insane. And there is nothing I can say beyond acknowledging my immense good fortune, and being aware that I'm blessed, and aware that it isn't going to last forever. You know? The tricky part is making it stick."
Making it stick. Despite his protestations, he's made a fine job of it - and all without venturing too far from his time-honoured, well-honed persona. Cast Away may have its hopelessness and melancholy - unlike his nearest peer Tom Cruise's actorly forays with Eyes Wide Shut and Magnolia, it doesn't oblige its star to attend orgies or use genital expletives. "Those movies are amazing things," he shrugs. "But I'm attracted to what I'm attracted to. I'm not interested in doing something edgy with a capital E just so everyone knows, 'Oh, OK, now he's showing us he can do edgy.'"
So would he have done Sam Mendes' American Beauty, thereby requiring him to masturbate, smoke dope and threaten his (male) boss with sexual harassment charges? "Oh, if I'd read it, I'd have done it. God, yeah. It's like, uh, any movies you wish you'd made? Yeah - that one. That would've been nice." Which, presumably, is why he's working with the director on Road to Perdition, playing a fictional henchman of Al Capone? "Well, partly. I mean, I've known Sam a while." Suddenly excited, he plucks a magazine from the table. Jude Law gazes out from its cover. "Jude Law is in it too!" he says. "Jude Law! Jude Law!" He waves the British actor's face in front of his own. I'm not sure what to say. He puts the magazine back neatly where he found it. "But that's another case where it's not a generic choice of what type of film I want to make. It's a very specific thing, where I know exactly where I'm going."
And wherever that is, his public will surely follow. Because, in a way that precious few film stars have ever become, even at his end of the firmament, Hanks, to his fans, is more than just a face on a magazine cover. He's one of them: an average Joe, an Everyman, America's fondest self-image made flesh. Nice is how he's routinely, inescapably described - nice to his co-stars, nice to autograph hunters, even nice to Monuriki, with the World Wildlife Fund thanking him for helping preserve the island's flora and fauna (including the crested iguana).
And nice he is, genuinely so. Except nice belies his brightness, a presence of mind sufficiently acute to know that no one is quite as nice as Hanks is supposed to be. Which must constitute some serious pressure. "No," he says. "It doesn't. It would if I slavishly adhered to that branding, and did nothing but attempt to cash in on it. But look, I was born in 1956, the peak year for births in US history. I think I'm very representative of many of the thought processes my generation have been through and, by and large, people of my age have had their imprint planted on the consciousness of western society for a long time. So that's how it adds up. I mean, I've pursued jobs that have fascinated me as an individual. The other stuff has just somehow miraculously fallen into some sort of place."
The other stuff meaning the awe-inspiring likeability which has long fuelled earnest talk - though not from him - of an eventual move into politics. The presidency is often mentioned. A reliable contributor to Democratic funds (albeit one who regretted supporting Clinton's impeachment defence), he bridles slightly when you raise the subject.
"Well, I'm politically aware. I talk about politics all the time, and I do so quite animatedly in the privacy of my own... salon. But actors with political views are a dime a dozen. And the only reason this comes up is that the New Yorker once ran a very funny article about me where their whole take was, 'Here's a guy that's running for president.' And it's insane. I'm not. Never have been. Never would. But once that gets out, there's nothing you can do about it. And I'm not apolitical - I'm very specific in my politics. But a lot of the time it's nobody's business unless you're over at my house having dinner."
Which is exactly the sort of decent, eminently sensible comment you might expect. I tell him the concept of President Hanks probably holds so much water because he's so obviously not the kind of guy who would ever want the job. Just like he's not the kind of guy you typically find with Hollywood in the palm of his hand. There are, after all, plenty of nice, smart people working at McDonald's. Yet, when you study his face for signs of how he made it from college drop-out to all-purpose icon, you come up blank. There's no dart in the eyes, no curl of the lip. Does he think he's ruthless? Careerist even?
"I don't think I am." He sounds as if he's considering the issue for the first time in his life. "No, I don't think I am." So how would he explain his success? "Well, you know, it's been a little pokey here and there. But... look, it's very hard to say no. And rather than being able to say yes to the right things, I think I've been able to say no to the wrong things. Which is hard, because a lot of the time the story is good, the people are great, and it's a nice chunk of change they offer you. But if it's not right, it's not right. And that requires a degree of discipline, and no small amount of understanding of the work you want to do. I think that's the only way we really get to define ourselves - not so much by what we say yes to, as what we say no to."
OK. Just so we're clear on this: there is no masterplan. Hanks does the parts he wants, and the parts he wants are the parts that interest him. Simple. In which case, what is it about those parts, besides their niceness and their perennial appeal to Oscar voters? Glance back through his career and the thread you find, running through Forrest Gump and Sleepless In Seattle, through Philadelphia, Toy Story and now - most definitively - through Cast Away, is loneliness. Loneliness and transience. And then it's hard not to think of Hanks at five, being spirited away by his hotel chef father, Amos, to spend the rest of his childhood moving nomadically around the suburbs of California, with a different set of stepmothers and temporary siblings every six months. He takes another swig of water. Is there any correlation there?
"Oh, I think there is. Sure. But I also think all of the great stories in literature deal with loneliness. Sometimes it's by way of heartbreak, sometimes it's by way of injustice, sometimes it's by way of fate. There's an infinite number of ways to examine it. And if there's a reason it always seems to be there with me, it's because it's so palpable to all of us. You can turn everything into an aspect of that battle against quiet despair, because we all fight it at some point in order to feel we're part of humanity. And sure, the work gives me a chance to re-examine that from the places I've been as a human being. But the battles against loneliness that I fought when I was 16 are very different from those I fought when I was 27, and those are very different from the ones I fight at 44."
So he's still lonely now? "Oh sure. Like I say, aren't we all? And I think that it's infinitely fascinating." There are two last questions I want to ask about Cast Away. The first is whether the name of his volleyball companion on Monuriki, Wilson, is coincidence: his wife of 12 years being actress Rita Wilson, sitting upstairs as we speak. "Oh, that was in the script," he says. "Anyway, it's a much better name than Adidas." The second concerns a scene in which - in a rare moment on dry, inhabited land - he finds himself driving to a crossroads. The symbolism's obvious, verging on the glaring. But does Hanks ever wonder about the road not taken? Or the road ahead? He looks at me like I've asked him to name the capital of France.
"Oh God. You don't think about that. That's not the important stuff." He stares at his bottle, his spoon, then me. "The important stuff is who else is in the car."
From drop-out to superstar
1956: Born in Concord, California.
1961: Parents separate. Tom goes to live with his father, Amos.
1976: Drops out of college (California State, Sacramento) aged 20 to pursue a stage career.
1977: First professional acting job, as Grumio in The Taming of the Shrew at the Great Lakes Shakespeare Festival, Ohio.
1978: Marries the actress Samantha Lewes.
1980: First film role of any significance, as a psychology-spouting student in the slasher flick He Knows You're Alone. Major career break via the ABC television sitcom Bosom Buddies, about two pals who have to dress in drag to stay living in their friend's apartment.
1984: First movie lead role, and first hit, with Splash. Its director, Ron Howard, originally auditioned him for the supporting role that went eventually to John Candy.
1985: Divorces Lewes. Marries the actress Rita Wilson after meeting on the set of the film Volunteers.
1988: Major hit with Penny Marshall's comedy Big, despite being third choice after Harrison Ford and Robert De Niro. Hanks receives his first Oscar nomination (loses to Dustin Hoffman for Rain Man).
1990: Cast as Sherman McCoy in The Bonfire of the Vanities, but is helpless as the movie tanks spectacularly.
1994: Wins his first Oscar for lead role in Philadelphia, Hollywood's gay-themed breakthrough. Forrest Gump released later same year and takes over $300m in the US.
1995: Wins his second Oscar, for Gump - the first actor since Spencer Tracy to win two in successive years.
1996: Directorial debut with That Thing You Do!, which he also scripted. Gives son Colin a small role.
1999: Fourth Oscar nomination for Saving Private Ryan (loses to Roberto Benigni for Life is Beautiful).
2000: Films Cast Away while acting as executive producer on the WW2 TV series Band of Brothers.
2001: Due to film Road to Perdition, Sam Mendes's follow-up to American Beauty.