James Corden: An ordinary man in an extraordinary world

The Into the Woods film had famously been in development for a long time – why is now the right time?
People have been trying to make this as a movie ever since it opened on Broadway, so I don't know how much of it is about timing. The first time it was meant to happen Robin Williams was going to play the Baker, and the second time Billy Crystal was lined up to play it, so I don't really feel qualified to be the third person on that list at the time it's actually made!

Isn't that testament to where you are in your career now?
I don't think so, no. I'm under no illusions that Rob had to fight for me to be in the film. There were lots of very famous people who would want to be in it. But the character is essentially an everyman who is representing the audience, in a sense, an ordinary guy in an ordinary world who enters this extraordinary three nights and ends up being a hero. So I think Rob was keen to cast an ordinary guy who the majority of audiences for the film wouldn't have seen before.

What was your audition like?
I wasn't auditioning for the movie as we know it now, I was auditioning for a workshop of it. I think because of that I was a little more relaxed. So I went along and sang a few bits from the show at the piano and Rob pretty much asked me there and then to do the workshop. And during the workshop my eyes were very open to the idea that if the film got green lit they would go off and cast someone very famous. But after the workshop Rob came to me as I was packing up my things and said, "I promise you, if we make this film I won't make it without you." I'm sure he faced some opposition from various people and I'll always be indebted to him that he was true to his word.

Would you describe it as a dream role?
Absolutely. There are some jobs that are just jobs, and some where you go 'this is all I ever wanted from my life and career'. Into the Woods is definitely in the latter category. It's one of Sondheim's most beloved and smartest shows, directed by someone who I consider to be the best musical movie director in the world. So no one's ever in a bad mood going in to work on a project like that.

Were you at all intimidated by the singing?
I didn't feel intimidated by the singing because The Baker isn't a particularly big sing, not least because his big song from the show isn't in the film. So intimidated is the wrong word – I was more just nervous that I could match up to Meryl Streep!

How was it to work with Meryl Streep?
She's very good at putting you at ease; she takes the work incredibly seriously, but doesn't take herself seriously in any way. She loves silliness, and being part of a company. If anything you feel like she's the leader of your company rather than separate from your company.

How did you react when you first saw the finished film?
My overwhelming feeling after watching it for the first time was one of pride. I just felt incredibly proud to be in it, and that will never change. I don't know that I've ever seen a musical on film like it, which is part neverending story, part comedy, part romance. The intricacies of it make it truly unique. When my son's older and I sit and watch it with him I think it will still hold up, and you can't say that about every film.

Tell me something you haven't told anyone else about Into the Woods
That's a tough one. Ok, there's a song called "Rainbows", which was in the very first version of Into the Woods but was subsequently taken out. It's a duet between the Baker and the Baker's Wife, and it was almost in the film. We rehearsed and rehearsed it, but for some reason it was jarring the story. So it was never filmed, though to be honest Emily and I both had doubts about it. There's also a brand new song called "She'll Be Back", which was written by Sondheim for the Witch. And it was filmed, but in the end it just didn't fit in the narrative, though I think it will be on the DVD.

Your chemistry with Emily is great – what's the secret?
She's amazing, and I really think she's giving the performance of her career so far in Into the Woods, which is saying something. I don't know how we found our chemistry, but a lot of people have commented on it to me. I'd love to say we worked on it for ages but it really was just there. I think the key is to know when she's being funny, and step back, and vice versa. If you've got two people trying to out-funny each other it just doesn't work. Doing "It Takes Two" is the best day of filming I've ever had in my life, ever. And not just because I got to do quite a flashy forward roll!

How are you feeling about hosting CBS's The Late Late Show?
I couldn't be more sight unseen to be sitting down and chatting to America every night, it's completely ludicrous! I feel utterly unqualified for such a task. I feel as if someone has said, "hey, you're joining the Sky Tour de France team", and I'm on the bike and saying "guys, you do know I can't do this, right?". But I'm really excited about the adventure of it, and the adventure for my family of moving to LA. I'm dreading saying goodbye to people here, but I don't know anyone on their deathbed who says "I wish I hadn't lived in that other country for a while." It's such a great opportunity, even if it's completely unfathomable that I should be doing such a thing.

You are of course a former host of the WhatsOnStage Awards – what are your reflections on that time?
What's amazing is that I was there at the beginning when it was just a small event, and now it's just this huge thing. When I won for One Man, Two Guvnors [in 2012], I turned up and people were in ballgowns and remember thinking "oh shit, I really should've dressed up more". What's brilliant about them is that there is no better judging panel than the theatregoing public, because without them it just doesn't exist. The audience are much more important than me, or anyone else on the stage, because the truth is you can always find other actors. But if you lose your audience it's over. And if we don't look after the audience, we'll lose them. So the WhatsOnStage Awards have rightly achieved a sense of gravitas and hope that grows and grows.

Into the Woods is released in cinemas across the UK on 9 January. To vote in this year's WhatsOnStage Awards visit awards.whatsonstage.com