Ben Whishaw made headlines in 2004, when as a recent Rada graduate he was cast by director Trevor Nunn in the title role of Hamlet at the Old Vic. He has worked extensively in film, television and on stage, and since 2012 has played the part of Q in the James Bond film series.

You’re about to play Brutus in a new Nicholas Hytner production of Julius Caesar – what’s your take on that role?
Well, I’m finding it really difficult at the moment. Shakespeare wrote the play just before Hamlet, and it’s got a Hamlet-like quality. What I’m finding quite difficult is that Brutus can make what turns out to be a bad decision – to assassinate Julius Caesar – and yet he never entertains the idea that he could have been wrong. He has such faith and self-belief. It’s interesting, because lots of politicians behave that way.

Do you ever doubt yourself as a performer at these times? Start thinking: why have they cast me?
Deeply. I’m in the middle of a crisis right now. I really am.

Sorry to hear that…
But it is normal. You go through it every time. But you still feel wretched.

Why do you think Hytner, the former director of the National Theatre, wanted Julius Caesar to be one of the first productions at his new London theatre, the Bridge?
Nick is obsessed with the way it seems to be suddenly so incredibly relevant again. We talk a lot about Trump obviously, Brexit and the rise of the populist movement. And I suppose in our production, the conspirators are what we would call now the metropolitan elite. They’re the conservative people; they want things to stay as they are. It’s Julius Caesar who’s leading the Trump‑like revolution.

Each night, there will be 250 “promenading” tickets. How will this affect the staging?
Nick is setting the play in a very contemporary world and we’ve got a woman playing Cassius, so it should feel quite different. And members of the audience will be standing, they’ll be the mob, really. So it will be pretty interactive, but not in a scary way: no one will be singled out for audience participation, but their presence is part of the performance.

You work a lot in film and TV as well as theatre. Is it very different to perform in front of a live audience?
I do find theatre harder work. When you finish a film or a television series, you know it’s going to be a solid thing that you can look back at and watch. But theatre leaves nothing behind and I’ve never finished and felt: “We did that well.” You just feel a continual feeling of slightly failing. And then it’s gone and it’s like: “Did we even do anything?”

In 2004, straight from drama school, you were cast as Hamlet by Trevor Nunn at the Old Vic. Do you feel like you haven’t had the struggle that a lot of actors have?
Well, I do recognise that was an amazing thing to happen. And I’ve been very lucky, but I mean, I don’t know what I’m doing after this. So you never know. But if it all ended it would have been really good to have had this much of an experience and I’d do something else.

When you started speaking out about being gay a couple of years ago, did it cross your mind that it might limit the roles you’d get?
No, I really didn’t care about that. I just wanted to be honest. And I still don’t care. I don’t feel it’s something that defines me, it’s just a part of who I am. And the world has changed so much in the last maybe five or six years, I think it is a less homophobic world, generally speaking.

Is it really only in the past handful of years that it has become more acceptable?
For me, I’ve felt a big change. When I did Hamlet, when I was first in the public eye, certainly there was no one my age who was an actor and out as gay. Nobody at all. And if you mentioned it to people it was a bit like: “Maybe don’t talk about that.” Or: “I hope you’ve got a good agent.” But I also recognise it was me as well. I hadn’t dealt with it, so I can’t blame it on the world. But certainly it was compounded by the fact that it seemed like not necessarily a good idea to be honest about it at that point.

As the voice of Paddington, how much do you engage with the rest of the cast?
Very little. They’ve done it all, they’ve filmed everything and I just work with Paul King, the director and writer. Well, that makes it sound like it’s just me and Paul. There are 2,000 people making that bear, who are extraordinary and working so hard. But yeah it happens entirely in the post-production, and it’s not that much fun until the bear starts to appear.

Are Paddington’s expressions your expressions then?
It’s a mixture. They film my face and my mouth, and sometimes we do little bits of physical work to start building the animation around. But they also have mime artists and it’s really cobbled together from lots of different things. It’s quite mysterious, even to me.

You’re not going to tell us anything about the next Bond film, are you?
I honestly know absolutely nothing. I think I’m going to be in it, but they haven’t told me anything. I don’t even know when we’re filming, haven’t read a script, don’t know who’s directing it. That’s the honest truth. It’s a funny process; I suspect they just haven’t written it yet.

Julius Caesar runs at the Bridge theatre, London SE1 until 15 April