Eddie, Steady, Go: The talented Mr Redmayne on Baftas, bankers and Birdsong

Every Christmas Eve, the actor Eddie Redmayne cooks a ham. He tends to this ham with the utmost care and devotion, adding a little brown sugar here; a few more cloves there. It takes him hours, if not a whole day. For those of us who partake regularly of the Redmayne ham – he and I go back a long way – and it seems to get better every Christmas, as if he's been quietly, stealthily striving to improve the recipe all year round. Yet no matter how magnificent it tastes, how tenderly it melts in the mouth, he will brook no compliments of the ham. Invariably, he will instead point out what he could, should have done better.

I am struck by the ham analogy during a recent interview with Redmayne. Exactly 10 years since he was plucked from Cambridge University to play Viola opposite Mark Rylance's Olivia in a 400th-anniversary production of Twelfth Night, he has just learned that his current performance as Richard II at the Donmar Warehouse has been crowned Best Shakespearean Performance at the Critics' Circle Awards – no mean feat, given that the season has also seen heavyweight Shakespeare contributions from the likes of Spacey, Tennant, Sheen and Fiennes.

In the intervening decade between Viola and Richard, Redmayne has worked fastidiously and uncompromisingly. Allergic to anything resembling complacency, he rarely takes a day off. Now he is talking to me over a cup of tea before heading back to the theatre for that night's performance, and he is radiant with excitement at the Critics' Circle news.

"It's just the loveliest, loveliest thing that could have happened," he admits. But where most actors would take such a prize as cue to relax and enjoy the last weeks of the run, Redmayne shakes his head. He's going back to work.

"Because you never get it right," he insists. "You never get it close to getting it right, you never get one line exactly how your notion of it should be. That's what's so exciting about theatre. Most actors hate watching their own films because all you can see is the glaring mistakes, your own tricks and ticks. But people often ask, how can you do the same play night after night for months on end and not get bored? And that's the reason. In theatre you always have the chance to try and fix what you did the night before."

It seems remarkable that the London-born Redmayne, who has just turned 30 and is having, by any definition, a golden moment, should remain so self-critical. As well as giving his Richard every night, making lines like "I live by bread like you, feel want/ Taste grief, need friends" seem revelatory, he is also gracing Sunday night television screens as Stephen Wraysford in a landmark BBC1 adaptation of Sebastian Faulks's Birdsong, and charming cinema audiences in My Week With Marilyn. As soon as Richard II closes, the former Eton and Cambridge choral scholar is off to play (and sing) Marius in Tom Hooper's big-screen musical adaptation of Les Misérables, with Russell Crowe, Hugh Jackman, Helena Bonham Carter and Anne Hathaway. And with major theatre awards from the Olivier to the Tony already to his name, he is now up for a Bafta – this year's Rising Star Award, which is voted for by the public – and looking, increasingly, like the one to beat.

But this is also the young man who was so unconvinced he would make it as an actor that he seriously considered other career options after graduating, including art history and banking (his father and one of his three brothers are in finance; nobody else in his family is in the arts).

"I didn't go to drama school, so there was no official transformation stage, no moment where I got a certificate, even a bit of paper, saying 'right, you're allowed to do this now,'" he points out.

"After university, I gave myself a year. I was working in a pub and doing excruciating auditions and wondering if my new agent who'd taken this huge punt on me would sack me, and I remember getting a part in an episode of Doctors and it was probably the most exciting thing that had ever happened in my life. Then I went to Liverpool to do a play called Master Harold... and the Boys and I was living in a hostel on my own for three months and it was the most wonderful experience. I started to think, secretly, 'well, maybe I can do this'. But I came back to London and nobody took any notice and I went back to work at the pub. I always felt a bit fraudulent, like I was waiting to be exposed." Munching a biscuit, he contemplates this. "In a way, I still do. I still feel this incredible sense of gratitude that anybody actually lets me do this professionally."

In any other actor, this might come across as galling false modesty. Given his current ubiquity, it's easy to imagine that Redmayne's success has arrived largely overnight; but that "star" to which the Bafta nomination alludes has been gradually rising for 10 years. It may also be tempting, considering the green eyes, 6ft 1in frame, and ridiculous cheekbones that have won him Burberry modelling contracts and a multitude of devoted fans both male and female – though he is currently single – to assume that this is just another talented pretty boy who happened to get very lucky. But ever since Rylance gave him that first big break, Redmayne has personified the old adage that luck is merely what happens when hard work meets opportunity. As his CV has swelled, so too has his dedication; the more professional triumphs that have come his way, the more he has put his head down and worked harder. He certainly takes nothing for granted.

"Listen, acting is not surgery," he remarks, "it's entertainment. You're doing something to hopefully move people, to make them laugh, to transport them. But actors are vulnerable, and the reason we're vulnerable is that we're always trying to recreate human behaviour. And any human being has the right to look at that behaviour and decide if it looks real to them or not. Everyone has that capacity for judgment, everyone can turn around and say, 'sorry, but I just don't believe that'. So if you have thin skin – and I don't have particularly thick skin – then your need to constantly please people, well... it's completely impossible. That's why I still feel I've got so much work to do, to really try and nail this thing.'

If the drama-school credentials are lacking, Redmayne is, by his own admission, a "sponge", and right from the outset he found himself in a formidable real-life classroom. "My first film, Like Minds, was with Toni Colette, who was extraordinary," he remembers. "I mean it was basically a mini-masterclass for acting on film at a time when all you could probably see were my eyebrows bouncing up and down on screen." We work out that, over 10 films, he has worked with at least 10 Oscar-winning actors, from each of whom he has learned valuable lessons.

"It's just the greatest luck," he maintains, sounding mildly incredulous, "to have been able to work with such brilliant people." But while these other actors may arrive in a rehearsal room or on set with their ideas fixed – indeed William Hurt, whom Redmayne worked with on The Yellow Handkerchief, has his preferred rehearsal method guaranteed by a clause in his contract – Redmayne subscribes to no fixed approach. He loves, he says, "to be part of a director's vision", and to mix the process up; whether it be Tim Carroll and Dominic Cooke's work with "intentions" or Michael Grandage's desire to get a play up on its feet almost immediately "so that he captures those instinctive things; whatever you do when you don't know the play well enough to be thinking about it."

Is there a quality that unites the directors Redmayne admires, I wonder? He considers this. "Taste?" he ventures. "Generosity of spirit? Certainly, they create an atmosphere of kindness and freedom, an environment in which an actor can really take risks, and they have the silent confidence of being sensationally bright." He clarifies. "I mean, the intelligence is never demonstrated or bragged about but it's just there – so you feel confident in their confidence."

I ask which of his directors most exemplifies these traits and he eagerly cites early experiences with Tim Carroll (Twelfth Night), Phil Willmott (Master Harold... and the Boys), Dominic Cooke (Now or Later) and Tom Kalin (Savage Grace), as well as more recent ones with Michael Grandage (Red and Richard II), Derick Martini (Hick) and Philip Martin (Birdsong).

So, pretty much everybody then. Is this just the Redmayne people-pleasing imperative in action, I wonder? Has he ever had a rubbish experience? He blushes, lowers his eyes behind a gulp of tea. "Well, there was one film I did – obviously I can't name names – but I was on set with a group of phenomenal actors doing a scene and struggling to make a particular line come alive and I had this great director standing over me going, 'come on, Eddie! I've seen you act on stage, I know you can do it, JUST MAKE IT LIVE!' It makes you... want to jump on the first plane to America."

Redmayne is a born-and-bred London boy, and seems almost as excited by the fact he has just had an offer accepted on his first flat, in Borough, as he is by his latest acting prize. But America has embraced him since day one; we have often joked how bizarre it is that he seems more at home playing dysfunctional, often gay Statesiders with distinctly warped backgrounds (most recently, a Texan serial-killing cowboy with a limp in Hick, for example) than well-balanced, well-educated, straight Englishmen from solid, happy families like his own.

"Oh, this is an argument I often have with my mum," he chuckles. "She always complains, "but so-and-so's just playing himself," and I have to remind her that it's actually incredibly difficult to play yourself! But the further a character is from what you are, well..." He thinks about this for a moment. "It's like jumping off a cliff or something, and there's a high chance you're going to end up with egg on your face. So if you're going to end up with egg on your face anyway then it doesn't really matter how much; so you leap at it and go all guns blazing. When you're playing someone closer to you, you're much more constrained. All you can hear is how wrong you're getting it.'

There's that self-deprecating reflex again, but the metaphors he chooses, mixed though they may be, are revealing. I remember being struck, as we rehearsed a university production of David Hare's two-hander The Blue Room in 2001, that this was not your average college thesp. He pushed me – pushed us both – to go places with our characters that were dark, risky and dangerous. This capacity for plumbing depths is beautifully served in Birdsong. His wartime Stephen Wraysford is damaged and raw, while the flashbacks to 1910 reveal a young man in all his idealistic, romantic passion. That fissure within Wraysford is what most appealed to Redmayne, who had devoured the book as a teenager but had read a number of previous adaptation attempts that didn't seem to, in his terms, "nail" that conflict. "The difficulty is that it's an extraordinary love story and then a World War One epic," he suggests. "And the way the love story works, it's clandestine; it's one of deep eroticism that needs to be built through the unsaid, and delivered slowly. How do you do that and then the wartime plot, especially in a single film?" Abi Morgan's version, though, did immediately impress him.

"It didn't compromise or feel like it was cramming story into time but it had a length and a breadth that allowed the characters to breathe. And she had this conceit where Stephen's idyllic interlude in Amiens as a young man falling in love is juxtaposed with him during the war as this masochistic, cold human being. Actually, I think maybe it's similar to what I've been trying to do with Richard II. The audience see these two fundamentally different people, really taken to the extremes, and there's this vexed question that has to play out through the piece of how they might ever be reconciled."

On the mention of Richard, Redmayne checks the time, then jumps up. He's due back at the Donmar to revisit his flawed, vulnerable, painfully human king; and somehow – who knows how – try to improve upon whatever it was he did last night.

'Birdsong' ends Sunday, 9pm on BBC1. 'Richard II' is at the Donmar Warehouse, London (www.donmarwarehouse.com) until 4 February. 'My Week with Marilyn' is in cinemas now