Into The Woods explores the complexity of our wishes and dreams and is perhaps most clearly seen in the story of this woman who yearns to be a mom – what she’ll do to become one and then what happens in the wake of her suddenly getting that wish. What’s your view of that?

Emily Blunt: I think out of all of the characters, in a way the Baker’s Wife is morally the most questionable. And you sort of understand it because she is just desperate to be a mother and she’s worked herself into a complete frenzy and distraction that she cannot put one foot in front of the other until she becomes a mother. It’s just that inability to see anything else other than the desire to be a mother. And she screws over all these poor fairy tale characters and takes and takes and takes and does it with humour. But she’s very deliberate and out of the couple she’s definitely the one who is prepared to go to any lengths to get what she wants and she does that. And then I think what happens in the second act when she becomes a mother, which is so joyful and amazing, is that she has to suffer the ramifications of the morally questionable things that she’s done. And ultimately, the dalliance with the Prince and all of that is, however exciting – and that song ‘Moments In The Woods’ is a song of great conflict – she’s debating…

James Corden: But that’s the only bit of the film I think is unbelievable. And I had this with Rob, I said to him, ‘I think people will believe giants and witches and beanstalks, Johnny Depp’s a wolf – no-one, and you back me up here, no-one leaves this [Points to himself] for that.’ [Points to Chris Pine] So I apologise. You’re right, it’s bullshit.

Emily Blunt: I’m going to put it down to sleep deprivation because no-one would obviously fall for this. [Points to Pine] I think that’s the tragedy of the character is that once she’s had this fling with the Prince and is in great conflict about it and is debating what she did and should she have done it and it was kind of amazing but oh my God I shouldn’t have done it and she realises too late and that’s the tragedy. And I think a lot of people can relate to that regretful feeling that life offers you sometimes.

James, can you tell us about your experiences working on the film and about working with the children? This is a chance to embarrass yourself or one of your fellow actors…

It’s so strange when you look at the film and it being about careful what you wish for and things like that. I’ve spent a good chunk of my adult life dreaming of being in a film like this and being in this show, even. We did a workshop of the show in New York two years ago for all the executives at Disney and it was very clear in my mind that we’d do this workshop and it’d be great and then they’d go off and get someone very, very famous to play the Baker and that’s what it would be. And Rob came and found me after the workshop and he said, ‘I promise you that if this gets made into a film you’re coming with us to do it.’ And it was the most incredible thing to hear. But even then I was thinking, ‘I know what it’s like when it gets to the business end of stuff – big film, famous people. And he just stuck by me in a way that gives you a confidence as a performer and he makes you feel like all of this would fall apart if you weren’t here, which just isn’t true – it isn’t, it’s not true. And then before you know it, you’re in a room just talking to Meryl Streep like this is something that you do. And you shit yourself, which is what happens. And then she’s amazing, she sort of knows how you feel when she walks into a room and she does everything she can to say, ‘We’re a company.’ And she led this company from the front. And there’s nothing you can say about her that hasn’t been said as a performer and as an actor, it’s incredible. But to meet someone who takes the work so seriously and is meticulous about the work – reading it, re-reading it, doing it – and is so serious about it as a piece and yet takes herself not seriously one bit makes the whole thing so much fun. And that’s very rare. Most times you only enjoy stuff on reflexion, you look back and think, ‘God, we really had a great time there, I didn’t realise.’ And every day – every single day – on this, I thought, ‘I don’t want this to end and I know this has enriched me as a person and as a performer and it’s the single greatest time I’ve ever had on a film set.’

Christine, is it safe to assume you’d seen Into The Woods performed before?

Christine Baranski: Yes, I saw the original production on Broadway.

With that knowledge, the role of the Wicked Stepmother is certainly an iconic character type in stories, so I’m wondering what you’re take on James Lapine and Stephen Sondheim’s Stepmother was? Having knowledge of how it looked and felt in the theatre, what did you bring to it?

Christine Baranski: She’s always described as mean and wicked and when you see it she’s always mean and wicked towards Cinderella and you have to examine that. Rob and I looked at it and thought, ‘Well who actually are these people and what are their motivations? What is her motivation and these two desperate daughters? And we really came up with a modern idea about these characters. For my money, they’re mean because they’re deeply narcissistic, they’re ambitious, they’re venal, that you could see them reading trashy magazines and watching reality shows and the red carpet and saying, ‘Oh I hate her’ and ‘She’s not skinny enough.’ They’re venal and that’s where the cruelty towards Cinderella lies – they almost don’t even see her, saying ‘Cinderella do this’ but ignoring her. It’s very interesting that once the Prince comes and sweeps Cinderella off her feet, the Stepmother realises that Cinderella’s going to be the one to get into the palace with the Prince and bows down, as that’s where our bread is buttered. It’s not just meanness, it’s a vicious opportunism and a way out. That’s where I think the energy of those characters, particularly the mother, is – in status and money and image. In that regard, it’s a very contemporary sensibility, the worst of our contemporary sensibility. That’s why I think they’re relatable. We do use the K family – do I dare say it?

Tracey, how did you relate to fairy tales as a child?

Tracey Ullman: That’s why I like how we’ve done this film – it’s like the Grimm’s Fairy Tales I read as a child. They were brutal! The mother was cutting off the kids’ feet to make the shoes fit. I like that on day one we decided that I was going to hit Daniel around the head. We’re supposed to do this sanitised version of it. He got sick of that, saying, ‘Can you just rehearse it. You don’t have to keep hitting me!’ One day I got so excited I was describing to Rob, saying ‘And when I come down the hill, I could hit him then. And I really hit Rob. And he was like, ‘Oh Tracey, can you just mind things.’ I was getting so enthusiastic. But I love that because they were so scary when I was a kid and then they got so safe, everything had to be nice and you’re so special. When I was a kid we did know how hard and frightening things were and I think we all got very safe and PC with the kids. I always love the Witch, the story of the Baker and the Wife, them wanting the food in the garden – I love that one. I love my cow! Isn’t the cow great? Don’t eat them. Like a dog she would go like this if I wasn’t scratching her head. You didn’t killer her, did you Rob? You know that barbecue we had on the last day with the crew. It wasn’t her, was it? She’s somewhere in a nice field isn’t she?

Rob Marshall: Yes she is. [He says with a grin]