Joel, the older by three years, has the sort of good looks and elegantly casual clothes you'd expect from a semi-retired west coast musician. Ethan, with his frizzy hair and more animated expression, seems closer to the kind of movie geek that you might expect. Together, they're the Coen Brothers, the coolest film-making siblings in the business, here in London to plug their latest offering, The Big Lebowski.
Set in Los Angeles at the time of the Gulf War in 1991, the "stoner comedy" stars Jeff Bridges as Jeff Lebowski, also known reverentially as The Dude, an amiable, middle-aged hippy who happily spends his time getting wasted and hanging out at the bowling alley with his pals, the prone-to-violence Vietnam vet John Goodman and slightly dim Steve Buscemi.
When some eccentric criminals types confuse him with millionaire Jeffrey Lebowski, Bridges finds himself embroiled in a labyrinthine mystery involving German nihilists, sleazy pornographers and dotty conceptual artists. Along the way, we get ruminations on everything from the Talmud to the nature of ten-pin bowling. It's an everything-but-the-kitchen-sink kind of a film, with more hits than misses, and some truly hilarious sequences, and continues the Coen tradition of quirky pastiche and hip, deadpan humour.
The obvious source of the pastiche here is the novels of Raymond Chandler, although, this being the Coens, we also get large dollops of Busby Berkeley, country-and-western, conceptual art and ten-pin bowling thrown in for good measure. As is often the case with Coen films, the closest reference point is the dialogue-driven, absurdist comedies of Preston Sturges, although Joel plays down the comparison: "Although I can kinda see it in terms of the fast and inane blather, we weren't specifically thinking of Sturges this time."
Perhaps it's not surprising. The one time when the Coens' particular magic just didn't work was on the self-consciously overblown Sturges homage, The Hudsucker Proxy - their most expensive film and their only box office disaster. Did they learn some hard lessons from that experience? "Well, it was only a lesson in that we know not to do The Hudsucker Proxy again," says Ethan wryly. "There certainly won't be a sequel to that. It shows you how hard it is to second-guess these things. If we'd had to predict in the abstract which would be the more successful, Fargo or Hudsucker, we would have certainly bet on Hudsucker. Fargo seemed like a very obscure regional exercise. In fact, Hudsucker made less than any other film we've released, and Fargo made the most. It's just very, very hard to predict, but you have to try, because you have to make some sort of estimation to justify the money you're going to spend."
Since the commercial, critical and Oscar-winning success of Fargo, they seem now to be in a similar situation to Woody Allen, he agrees - more or less free to make what they want, within certain budget limitations. "Yeah, that's about right, as long as we don't spend too much, we're probably free to do whatever little things we dream up, which seems like a fair bargain. So we're in a pretty fortunate position."
Like Allen, the Coens are the sort of film-makers who actors will kill to work for. Certain names - Steve Buscemi, John Turturro and John Goodman in particular - crop up repeatedly, and the brothers are prepared to wait until they're available. The Big Lebowski, in fact, was due to go into production three years ago, before Fargo, but John Goodman wasn't free at the time.
"Every script we've written, there's been certain parts written for specific characters, and others where we don't know who it's going to be. Barton Fink was written with the two Johns (Turturro and Goodman) in mind from the start," says Joel.
In his third role for the Coens, Goodman plays a spoof version of the crazed war veterans who have been such a staple of modern American movies, with the added twist of being a committed Orthodox Jew (the nearest the Coens have come to drawing on their own Jewish roots). Incapable of holding a conversation without bringing Vietnam into it, he's a disastrous time bomb ready to go off at any moment. Like Bridges, he's trapped forever by his memories of his own past. "But these characters are all throwbacks in a way, defined by their experiences in an earlier age," says Joel, citing the "nihilists" in The Big Lebowski, a bunch of European art-rockers who have taken to kidnapping to pay the rent. "The nihilists are trapped in the 1980s. There are these kind of fringe rock 'n' roll guys in LA. You'll see them in late-night diners on Sunset dressed in black leather with long stringy hair, and you can't quite figure what they're about."
This affectionate portrait of the seedy sideroads of Los Angeles is heightened by a typically opaque Coenesque quirk - The Big Lebowski is a period film, set in far-off 1991. There's no apparent reason for this, beyond the opportunity it provides for some Saddam Hussein gags and a chance to laugh at the huge, bulky mobile phone which plays a significant part in the plot, but don't go looking for reasons in Coenland.
"I think the phones were already out of date at that point, but we just had fun with all that stuff," is as far as Ethan will go. You sense that the brothers are at their happiest with "all that stuff" - they go into a riff together on the particular brand of American jockey pants worn by Bridges in the film. It means nothing to me, but these are the kind of details they love, and who can argue with the proposition that nothing defines a man more clearly than his choice of underwear and the music he listens to?
"This character is defined by the fact that he loves Creedence and hates the Eagles," says Joel when I ask whether The Dude is one of the failures left on the hard shoulder of the west coast dream. "I think he has so little ambition that he's not a failed anything. There is a laid-back subculture in LA, that draws on the surfing lifestyle. It's partly the weather that makes that kind of stoner culture possible."
In The Dude, they've created one of the first pot-head heroes the movies have seen in years, I point out. "Yeah, it's too bad," muses Ethan. "It's something that's been frowned upon, maybe because of a new puritanism in the movies." The woozy, slightly blurred feel is more reminiscent of Robert Altman's fine adaptation of Raymond Chandler's The Last Goodbye, he agrees. "We definitely know that movie, and we were thinking about it in a way when we were making this."
The marijuana haze gave them ample opportunity to indulge in the movie's big set-piece, a dream sequence that parodies Busby Berkeley musicals through the drug-addled haze of The Dude's brain. "We've always loved Busby Berkeley, but it was more us trying to imagine what a pot-head who was slipped a Mickey Finn would dream about, what form it would take. That gave us freedom to do just about anything we wanted, so we came up with Busby Berkeley, Saddam Hussein and Kenny Rogers."
In the mid-1980s, their debut, Blood Simple, seemed like a bolt from the blue with its combination of comic-strip visuals, film noir references and movie in-jokes, but the Coen brothers' influence has grown to such an extent that you can see their trademark style imitated by half of the American and independent movies released each year. Suggesting that they've become the elder statesmen of indie cinema, I mention last year's A Life Less Ordinary as an example of how everybody's jumping on the bandwagon, but Ethan disagrees.
"Danny Boyle and those guys, they've got their own kind of stuff. When it comes to elder statesmen, I think Robert Altman still holds that position. Personally, I don't want to be an elder statesman of anything, I don't even want to be a statesman."
The Big Lebowski opens next Friday