Well, Kinnear eats the nuts; Lester just drinks the water. Kinnear, who is playing Iago in the new production of Othello that opens this month, is unshaven, lived-in, a touch dishevelled. Lester, even after a day's rehearsal, is fresh, lithe, athletic. He will be a cruiserweight Othello rather than the usual stately galleon.
The conspiratorial closeness may be appropriate. In their reading, Iago and Othello – long-time army buddies – used to be bosom chums. As with Hamlet, says Kinnear, the backstory is important. "You have to try to create a sense of the kinship and dependency they have had for the past 12 or 13 years." The brutal end of their friendship is part of the tragedy.
Too often in Othello, Iago's motives for doing down his former comrade can be obscure, but Kinnear insists his villainy is explicable. "He's been passed over for promotion in favour of the gilded classes like Cassio, and he suspects Othello has slept with his wife so is himself torn up with jealousy. Iago says it in his first soliloquy."
Kinnear explains all this with a quiet intensity and voice so hushed my tape recorder barely picks him up. His mother Carmel Cryan once told him he was too clever to be an actor, and you see what she meant. He studied English at Oxford and considered becoming an academic. For Othello, he says he read a lot about war and its effect on those for whom conflict is a way of life. "Both Othello and Iago seem a bit cracked," he says. "If you spend 15 years being responsible for death and destruction, that sense of suppressed horror is strong."
The production, directed by the National's outgoing boss Nicholas Hytner, is taking the idea of Othello as a war play so seriously that it enlisted a military adviser – the recently retired Major General Jonathan Shaw. "He has talked to us a lot about the kinds of people Othello and Iago would be," says Lester, "both non-commissioned officers coming up through the ranks and having a different set of muscles to those who have been trained to be officers. These guys have worked in the field and their skill is in staying alive when it's kill or be killed, and here they are basically running this army base."
Hytner, who prefers to play Shakespeare in contemporary settings, has updated Othello to the British army of the past 20 years. Othello and Iago are likely to have fought together in Kosovo and the Gulf. Now, as the engagement on which they thought they were embarking stalls, their personal animosities take over. War is carried on by other means.
"We knew we were looking at the modern army," says Lester, "and for me then I started looking at someone who wasn't born in Britain, but has joined the army from a Commonwealth country." Othello is usually seen as a figure defined by his race, but Kinnear says that in this play strikingly little is made of Othello's colour. "It's only ever used by people who have a grievance with him, largely Iago and Brabantio, Desdemona's father, as a last resort in namecalling. Certainly no one in the army ever brings it up, or doubts that Othello should be the general."
Lester says Othello's otherness manifests itself most in his speech, which is orotund – Iago calls it bombastic – and self-conscious. At first this worried him. "It felt that everyone was speaking in broken rhythms and a very modern Shakespeare form of delivery, and then my line would come – lah di dah di dah. There's a stateliness about it, as if he's hearing the sound of his voice as he speaks. So I went home thinking why can't I be unselfconscious and get into the character? But then I realised it's because the character is self-conscious, at which point I thought 'just embrace it'. He's trying to be this person who has the right to be in charge."
Othello is a role Lester always knew he would play – a rite of passage for any black male actor. "I hate to use this phrase," he says, "but I wondered when I would 'give my Othello'. It really did feel like that. You're male, you're doing Shakespeare, you're a certain age, it's going to come along." He almost did it 15 years ago, but was scooped up by Hollywood to appear in Primary Colors. "It was the right decision to go and do the film," he says, "and also I'm thankfully getting better as an actor. I feel better equipped to do it now."
Lester has come to Iago immediately after playing pioneering black actor Ira Aldridge in Red Velvet at the Tricycle, a role for which he was named best actor at the Critics' Circle awards. Aldridge enjoyed great success in the middle of the 19th century, and Othello was his theatrical calling card.
"Having played Ira first, it helped take the lid off some of the scenes in this version," says Lester. "But the two scenes that I did in Red Velvet I had to unlearn for this one, because I'd learned them in such a histrionic, declamatory style. When I do the scene with Desdemona and the handkerchief, I still hear myself doing it for Red Velvet and I'm tempted to strike the legs wide and cover my brow."
Maybe later in the run, I suggest.
"At a matinee," he laughs.
So, whose play is it – Othello's or Iago's? Lester accepts that, as usual, the devil has most of the best lines. "Iago is amazing. He picks apart every character and knows what will work on each person. His language and his imagery change depending on who he's talking to. It's an incredible study, and you get inside his mind."
Kinnear nobly suggests shared billing. "In the first half Iago is the engine of the play, but it gets to a point where he's no longer the puppeteer. He's just trying desperately to keep all the plates spinning, and it becomes very much this appalling tragedy of a man in absolute torment." But Shakespeare's great trick, he suggests, is to make the audience complicit in Iago's villainy. "He's afforded seven soliloquies to get them onside. That's part of the horrendous joy of the play."
Both Lester and Kinnear have hugely successful film and TV careers, but they insist nothing gets the juices flowing quite like a play. "I get antsy if a year goes by without doing a play," says Kinnear, who emphasises the sheer physical effort of stage acting. "I don't go to the gym, so this is my way of trying to live longer."
"If you're doing nothing but film," says Lester, "part of you gets soft – your speed of thinking, the amount you have to learn, your physicality, your voice, your diaphragm. When I step back on stage I have to re-engage all those muscles, especially with Shakespeare. You have to make the audience believe this is a real person speaking, not someone standing there reciting poetry. It's quite an ask."
Can it be done, especially in a play we feel we know so well? "People's preconceptions are based on generalities," says Lester. "Our job is to be very specific, and in that specificity to make it real, to make it live again."
How do they know if they're succeeding? "You can feel the audience's intake of breath," he says. "Even the people we've had watch it so far, the little reactions, the ripple from them tells you they've got it. A little nervous laugh as something else terrible happens tells us we're in there. 'Got you!'"
guardian.co.uk © Guardian News and Media Limited 2010