Eddie Redmayne on becoming Sir Stephen Hawking

Over the coming days and months you will be seeing a lot of the 32-year-old Londoner. His new film, The Theory of Everything, in which he plays the cosmologist Professor Stephen Hawking, is attracting the kind of Oscar buzz that can probably be heard from space. After that comes Jupiter Ascending, a science fiction fantasy directed by the Wachowskis which also stars Channing Tatum. Then Redmayne reunites with Tom Hooper, his director on the triple Oscar-winning Les Miserables, for The Danish Girl, playing Einar Wegener, the artist who, in the 1930s, was one of the first to undergo sex change surgery.

One might advise "Steady, Eddie", but Redmayne has already given himself that particular talking to.

"Buzz is worrying because it's an ephemeral thing. If you read the good stuff you also have to read the bad stuff. I try genuinely to just put my fingers in my ears and put one foot in front of the other. If you get caught up in listening to what too many people have to say that's where madness lies."

He says this while conducting interviews in Claridge's hotel in London. It is the latest stage of a publicity campaign for the film that will run all the way to the Academy Awards on February 22.

The film opens in 1963, before Hawking is diagnosed with motor neurone disease. Redmayne spent time talking to specialists and meeting people with the condition. His aim was to play a person rather than a disease, but he had to know enough about it so that he could convey its progressive nature. To learn about Hawking the man he started with the book on which the film is based, Travelling to Infinity: My Life with Stephen, by Jane Wilde Hawking, his first wife. Homework done, he then prepared for the viva of his life - with the author of A Brief History of Time himself.

"I was so nervous by the time I met him because I had just spent four months immersing myself in everything Stephen Hawking. Then you get to meet the guy and there are these long pauses. I'm nervous of silence in the most normal of situations, let alone meeting Stephen, so I just started spewing forth information about him, to him."

Hawking, who speaks with the aid of a voice synthesiser, had just published the book My Brief History. In it he pointed out that he was born on January 8, 1942, 300 years to the day Galileo died. Redmayne takes up the story again.

"I was filling air and said, 'Actually, I was born a couple of days before on the 6th of January, so we're both Capricorns'. As I said it I was thinking what a ridiculously stupid thing to say. He sort of looked at me and took a few minutes to write a response. Then he said, 'I am an astronomer, not an astrologer'.

Hawking has seen the film and approved to such an extent that he gave the makers permission to use his own, copyrighted, voice rather than an approximated version. "It was very moving for me when he did that," says Redmayne.

A week tomorrow [JANUARY 11] are the Golden Globes, where Redmayne is up for best actor for The Theory of Everything, one of a total of four nominations for the James Marsh-directed film, including one for Felicity Jones who plays Jane. To lift the award Redmayne will have to beat a fellow Brit, Benedict Cumberbatch, who is nominated for The Imitation Game. Yes, the British are coming. Again.

Make that the English. Though he has a grandmother who lives in Edinburgh, Redmayne, Eton and Cambridge, was made in England in the same way as Cumberbatch, Dan Stevens, Damian Lewis, Dominic West and the rest of the privately educated generation of British actors now as much at home on Hollywood Boulevard as Shaftesbury Avenue.

Redmayne's parents are both in business, but they were never anything but encouraging of their son's career choice, says Redmayne, who has two brothers and a half-brother and sister. He knew what he wanted to do from the age of 10 when he appeared in a West End production of Oliver.

"I was workhouse boy number fortysomething, but it meant I could leave school in the afternoon and go to the theatre. It was the Palladium, this huge barrel of a theatre with all these weird nooks and crannies backstage. I got completely intoxicated by it."

When he went to Eton his choice was confirmed on meeting Simon Dormandy, his drama teacher. "He had been an actor himself. He treated us like professional actors, made us step up our game. I always say the training I got was from him." His fondest memory of Eton was the drama. "It was an extraordinary privilege going there. I had quite a lot of interests, I enjoyed music, sport, art and drama, and the amazing thing about that place is the facilities. If at that age you have an interest in something you can fly."

There is a group photograph featuring Redmayne from his time at Eton which was published in the Daily Mail in February 2012. At first glance it calls to mind a certain Bullingdon Club photo, except all the participants look cheery and nice rather than sneery and not so nice. One row up from Redmayne, at the edge of the picture, is one Prince William.

Are people always asking about Prince William, say I, trying to find a way of asking without seeming to ask. "Occasionally," he says, "but it has been 12 years now so less often. I was at school with him and he was a lovely man but I haven't seen him since."

It is the kind of smooth, polite response which fits the bill of answering the question without saying very much. The only time Redmayne looks slightly wary when being asked about his upbringing is when I wonder if coming from such a privileged background is not a disadvantage for an actor.

"I don't think I could ever say it was a disadvantage. I'm absolutely aware of how lucky I've been. I wouldn't be an actor if it wasn't for that drama teacher. I was very lucky to meet this brilliant man who was incredibly inspiring."

But would he feel able to take on any part? Could he, for example, play a miner? It is a slightly tongue in cheek query, but there is a point here. Acting, after all, is about convincing an audience to suspend their disbelief, to make them believe that someone can be another person entirely. Redmayne, who has modelled for Burberry, disagrees with my theory.

"Oh, I don't think actors should be in any way... actors are actors. We should be able to hopefully play all different types of people from all different backgrounds, countries, and I'd like to feel I have done a wee bit, played lots of characters in America, lots of different people, so I hope not."

The same charm comes to the fore when I ask him about marriage. A few days before, a Sunday paper has run a story saying he and his fiancee, Hannah Bagshawe, will marry before December is out. Will he be married by the time this article is published? He smiles. "I'm not going to say, if that's OK." A week later it was reported that they had wed.

After several stage roles, Redmayne, still at university, moved into television. His first gig was Doctors. "Oh my God!" he shouts when I remind him. "The first scene was shot in a garden in Birmingham and in this particular episode the guy playing my dad was going to have a heart attack. I had no idea what I was doing. I think the guy playing my dad thought I was pretty useless and appalling which I was. But I thought I would get away with it Scot-free because I didn't think that many people watched Doctors." He had forgotten, alas, that students made up a large part of the Doctors' audience. "I got a surprising amount of text messages going, 'Just saw you being pretty appalling in a daytime soap'."

It did him no harm. Besides working on stage, he won parts in The Good Shepherd, directed by Robert De Niro, Elizabeth: the Golden Age, alongside Cate Blanchett, and Stephen Poliakoff's Glorious 39. The years 2011 and 2012 were the breakthrough ones, with toasty reviews for his performances in My Week With Marilyn, with Michelle Williams playing Monroe, the television adaptation of Birdsong, and Les Miserables.

All experiences he will remember, Birdsong more than most. One of the greatest boons of acting, he says, is being given the chance to learn about subjects. As part of his preparation to play a British Army lieutenant in the First World War, Redmayne visited the battlegrounds in France, where he was shown one of the tunnels in which the underground war was fought.

"There, inscribed in pencil, was a poem which said "If in this place you are detained, don't look around you all in vain, but cast your net and you shall find, that every cloud is silver lined. Still." This idea that someone had been down there, in that claustrophobic space, with all that noise above, with the high chance he was going to be buried alive there ... "But cast your net and you shall find that every cloud is silver lined". It breaks my heart even thinking about it."

In My Week With Marilyn, Redmayne played Colin Clark, a young runner on The Prince and The Showgirl who was assigned the task of looking after the Hollywood star. Monroe was to become the ultimate Hollywood cautionary tale, an example of the business's ability to eat its young and vulnerable.

Redmayne does not need to worry about such things. He has the good sense to enjoy his success and laugh about the failures, such as the time he went for parts in Star Wars and The Hobbit, both without success. "I've been up for so many films, you have to get used to it, to get quite thick skinned." In the case of Star Wars, he wheeled out his best "sci-fi baddie" voices. After the umpteenth attempt, he heard the words every actor dreads: "Have you got anything else?"

One of his notable stage roles of recent years was playing an assistant to Mark Rothko in Red, for which he won an Olivier. Something which stuck with him about Rothko was that he would turn up to work in a suit at 9am, get changed, paint, then don the suit again. It was his way, says Redmayne, a graduate in art history, of creating structure and putting form on the formless. One feels Redmayne would ideally like to do the same with acting.

This was difficult with The Theory of Everything because it was shot in London. "Your friends and family feel that you are around, but actually you're working from five in the morning till 10 at night six days a week. You are emotionally unavailable." Far better, he feels, to be on location, do the job, and go home.

He is smart enough to know that in the universe of film, television and the theatre, stardom can be a fleeting thing, often outwith an actor's sway. "The complicated thing with acting is that however brilliantly successful or good you are you are not in control really. Unless you start producing your own material or writing, even then it's a complicated world."

How does he handle that?

"I'm still learning, I don't know if I've got it down at all."

Steady Eddie, then, after all.

The Theory of Everything,12A, is in cinemas now