Jim Rash and Nat Faxon did not get a lot of airtime at the 2012 Oscars. They took to the stage to receive their awards for the script of The Descendants, but it was their co-writer, Alexander Payne, who did all the talking.  And yet you may remember them anyway. For they didn't just stand stiffly by. No: these were the guys who legbombed Angelina Jolie. That is, they copied the pose recently struck by the award's presenter: hand on hip, right leg thrust far out in front, head tossed proudly back. Sure, they were wearing tuxes, not a split-skirt silk number, but still, the effect was impressive. The audience hopped to their feet, the net went nuts, and, a few minutes later, the leg had its own Twitter page. Rash and Faxon made waves without saying a word.  It was, said Rash, who initiated the Angelegging, meant as a "loving tribute". "I had just seen her pose and thought it was bold and fun. And you know what? We have exactly the same legs."  Eighteen months later, their pins are back on display in the basement of the Covent Garden hotel. Both men are clad in khakis, strangely sober amid the busy furnishings. They're sat side-by-side on a sofa, in matching positions, a can-can of crossed ankles. Rash is slight and shorn, bright and twinkly. Faxon – who Jay Leno identified as looking like a Kennedy who has been hit with a pipe – grows giddy with rememberance. "That night still feels surreal and out-of-body, dreamlike and incredible and wonderful and magical," he says. "I still look at that statue in disbelief. I love thinking about the memory of that night, but what I love most is that it provided opportunities. I love thinking about it in that way."  Indeed. Rash and Faxon struck not just while the iron was hot, but while the statuettes were still in the furnace. Later that spring, they shot their first film as directors as well as writers (they also pop up in the supporting cast). The Way, Way Back, a bittersweet coming-of-age comedy, premiered at Sundance this January, where it was snapped up by Fox Searchlight for $10m, and groomed to follow previous acquisitions Little Miss Sunshine and Juno.  Its overlap with the first isn't just tonal: it starts and ends in a car, with Toni Collette and Steve Carell. But while in that first film they were siblings, here they're lovers, off for their first extended vacation in his Massachusetts beach house. The car also contains each of their children. Trent (Carell) has Steph, a bitchy blonde senior; Pam (Collette) comes with Duncan (Liam James), a gauche 14-year-old, and the film's de facto star. The opening scene shows Trent pep-talking his potential stepson while the women nap. He asks him to rate himself out of 10. Duncan stumbles towards a six. Trent corrects him: he's a three, and this summer he needs to shape up.  That same exchange happened to Rash himself, with his then-stepfather, in about 1984, when the film was supposed to be set before budgetary constraints kicked in. This direct psychological trigger explains the film's mix of emotional soap (climaxing in cathartic vindication) and nostalgic comedy. Strongest are the performances: Carell brilliantly mean and smug, Allison Janney off-the-leash as a boozy neighbour, Sam Rockwell perfect casting as the goofy manager of the local water-park, who takes Duncan under his wing. Faxon and Rash cameo as two of Rockwell's employees: the former as a genially pervy surfer type, the latter catty and languorous behind Dahmer specs and a kinky tache.  It's a fairytale, right? What with the wicked stepfather, the fairy godfather, the Oz-ish setting and the happy ending. "Hopeful," corrects Faxon. "A hopeful ending." He directs a loafer at his companion. "Yes. Your character is the buffoon."  Rash cackles. "Or the weird guy at the bridge who won't let them cross. The curmudegeonly troll."  "And I'm the prince or the stallion. Very important eye-candy, anyway."  "I saw you more as Humpty Dumpty," says Rash. "A blobby guy who sits on a chair, says some things and then falls."  "OK. Humpty Dumpty or a pegasus."  And, just like The Descendants, The Way, Way Back shows strained relations in an apparently ambrosial setting, fishes out of water washed up and scrabbling. Duncan shares DNA with both the George Clooney character in that film, tip-toeing out of the shallows, and with Shailene Woodley, who played his daughter. The scene in which she submerges herself in the pool after learning her mother is dying finds an echo in Duncan's trip down the water park's top chute. "It's a rebirth," says Rash, with a happy shrug. "You go through a water channel."  And while The Descendants finished with a picture of single-parent family contentment, as Clooney plus daughters share ice-cream on the couch, so this too cheerleads a non-nuclear option. Collette's character is neglecting her son in favour of her new boyfriend because she thinks that is in everyone's longterm interests. Says Rash: "She's lost in the idea that having a man is what she needs to complete this family. It's a false one because she's never trusted herself. Trent and Owen are the same thing in different capacities. Trent's way to teach Duncan to be a better man is to cast him out, and Owen is inviting him into the fold in a very nurturing way."  While the grownups run wild, Duncan gets a job and becomes a man. "I think that getting responsibility and structure are huge parts of growing up," says Rash. "For young boys, just to know you exist in any capacity is a strong feeling."  Rash and Faxon first met at LA improv company the Groundlings, when Rash was close to 30 and Faxon still nearer 20. Is what drew them together still what they like about one another?  They look sheepish. Rash says pertly: "Yeah, it's like when you're first in a relationship and you love all the things about someone, and then the real person comes out and you think: 'Well, I've already put in a lot of time …' I probably revealed worse attributes as the years went on, which could make him wanna bail. But despite the age gap we grew up together. You're very different at 25 than you are at 30, it's a key time, especially for this one, who was very immature."  Faxon gurgles a giggle; they talk about trying to have fun away from work. Says Faxon: "You need to make time for those moments. Because it is like a relationship."  Rash: "But you also have to celebrate what's important to us in our personal lives. Nat's got three kids and is married and obviously they're all important to me as well, but we also have our acting lives, which up until now have been pretty separate."  And here they do indeed diverge. Rash (102k Twitter followers) has a regular gig on cult sitcom Community, as a college dean forever debuting new insane outfits. Faxon (4.5k) has been less lucky: a new sitcom in which he was well-received as the lead, Ben and Kate, was recently cancelled midway through an episode shoot. Of the two, he seems the more vulnerable; when they discuss the Groundlings, Rash speaks of its commitment to character-based laughs, rather than just gags, while Faxon highlights its competitive setup.  "It's highly selective and so I think the cream really does rise to the top. You are inspired by what other members are doing and you're trying to achieve something similar or more than that so you're constantly being pushed. That can sometimes make you bitter but for the most part it does encourage you to up your game and try harder and then remain goal-orientated."  The workplace they've created in The Way, Way Back is the opposite: an egalitarian commune without professional jealousy or ambitious edge. And it must be odd, 18 months after an Oscar win, to still encounter hurdles.  Both men take courteous umbrage at the snobbishness in awards circles towards comedy, but it's Faxon who treads with most care. "Obviously Hollywood is based in fear more than it is in courage. That's an unfair blanket statement that will upset people. But it is a safer choice to do something that has a built-in audience."  Ask about directing duos they admire and they mention the Coens, and the husband-and-wife team who shot Little Miss Sunshine. They hum in unison, trying to think of more. What sets Rash and Faxon apart is, in part, their lack of actual relation. They speak about each other with the fondness of those who don't automatically assume its reciprocation. "There is something wonderful about experiencing all this with somebody else," says Faxon. "Having the lows together is comforting and there's something so gratifying about sharing the highs together. It feels so much more exciting."  • The Way, Way Back: first look review• Pass notes: Angelina Jolie's right leg
Catherine Shoard: They stole the show at the Oscars when they legbombed Angelina, but the writer-directors of The Way, Way Back are serious about their comedy