In the comedy Unfinished Business, a hard-working small business owner and his two associates travel to Europe to close the most important deal of their lives. Dan Trunkman (Vince Vaughn), a businessman in the apparently competitive field of mineral sales, quits when has finally had enough of his tough-as-nails boss, Chuck Portnoy (Sienna Miller), and starts his own competing firm, and takes the forced-to-retire numbers man, Timothy McWinters (Tom Wilkinson) and the positive-thinking but slow-witted sales applicant Mike Pancake (Dave Franco) with him, and sets out to close a massive sale.

During this exclusive phone interview with Collider, actor Nick Frost (who plays deal-sealer Bill Whilmsley) talked about why Unfinished Business was a no-brainer for him, how welcome Vince Vaughn made him feel, going to see Fleetwood Mac while they shot in Berlin, and how much they played with the script. He also talked about how incredible it was to play Santa Claus on the last Doctor Who Christmas special, how excited he is to explore the character of Nion more deeply in The Huntsman, where things are at with another Tintin movie, that he talks with Simon Pegg and Edgar Wright about working together again all the time and that they have some great ideas, but nothing set up yet, writing a memoir, and how he approaches the acting process.

Collider: When you read this script, what was it that stood out for you?

NICK FROST: I hadn’t read the script, at first. I had a lovely phone call with Ken Scott, the director, and Todd Black, the producer, and they did that thing that an actor is always really flattered by, when they phone up and say, “Hey, we really like your stuff and we’d like you to come on board. Let us send you a script, and we’ll go from there.” So, I looked at the script and it was great. I like Steve Conrad a lot. They did that thing where they allowed me to do what I wanted, and we improvised a lot. Once they knew that I wanted to do it, they gave (my character) Bill a lot more to do. It was the chance to work with Tom Wilkinson and Vince [Vaughn], who I’ve been an admirer of for a long time, and Dave Franco. To use an American colloquialism, it was a no-brainer.

This film has a great cast, and a lot of the smaller parts have really cool actors in them. What was it like on set? Was it just a crazy, fun atmosphere?

FROST: It was, yeah. We were all in Berlin for a month, and then we were all back in Boston. There was tons of hanging out, chatting and bullshitting. It was great. We all hung out together. Being a fan of Vince, I was a bit nervous going on someone else’s set, essentially, which is what it is, but I couldn’t have been made to feel more welcome. He was generous, and not just on set, but off set, too. It was a pleasure to sit and listen to the stories that invariably actors tell, and bullshit. I wound Vince up a couple of times, by asking him questions about his fantasy football league, which he loves. He spent a lot of time talking me through fantasy football.

Do you have any particularly fun behind-the-scenes stories or memories from the film that you can share?

FROST: There were so many. My brain is not built like that. Vince and Steve Tisch, the other producer, paid for us all to go watch Fleetwood Mac while we were in Berlin, which was amazing and really long. I was like, “These guys are 70. How can they do a four-hour set?!” I remember about an hour and a half in, I whispered to Dave [Franco], “Let’s just go!” But, we were there for the long haul. Everybody was funny and cool. There was never a day on this set where there was a bit of tension. It was just people hanging out and having a laugh while making the movie.

Was there any one person who broke the most and ruined the most takes on set, or was everybody able to hold it together pretty well?

FROST: My character has a massive crush on Dave’s character, so a lot of the time, I would just look at him and smile, lazily. I was trying to make him laugh on set. I would shuffle nearer to him, if he was next to me, or I would put my hand on his hand, just trying to make him laugh.

How was it to work with Vince Vaughn?

FROST: He never kept anyone waiting. He was punctual. He knew everyone’s name. He was very generous, with his improvisations and off set. There was always a coffee coming around, or some vehicle with some candy in it. He looked after everyone. I really like him, as an actor. I think he’s a fantastic actor. There were a few times when I had the chance to sit in a scene and watch him act, and it was great. I think I’m pretty lucky to have worked with him, and I hope I get the chance, in the future.

How much did the story and script change, from when you got the project to what we see on screen? Was there a lot of coming up with funny stuff, in the moment?

FROST: Yeah, absolutely! These things always change, especially on American pictures. You make sure you do it how it’s written, and then it’s fair game. If someone had an idea, it was never shot down. It was always heard and listened to. If something is funny, then it’s funny. If it’s not funny, then it’s not.

Seeing you play Santa Claus on Doctor Who was one of the most awesome things I’ve seen, in a long time.

FROST: Thank you! I loved doing it.

What was it like to be a part of Doctor Who, and how insanely awesome was it to be playing Santa Claus?

FROST: It was incredible! I thought it was amazing. I was in the pub, having a pint at 5 o’clock one night, when I got the phone call to say, “You’ve been offered the guest lead on Doctor Who.” It was fantastic to be Father Christmas, or Santa Claus. I happened to have a really big beard, at the time, so that was just my own beard, which I love. To get to spar with Peter Capaldi, who I think is an amazing actor and a fabulous Doctor, was great. He’s not really a giggler, but there was something about me and him that I could just get him to giggle a lot.

Are you someone who had ever wanted or hoped to be a part of Doctor Who before that?

FROST: No, but I’m happy to do whatever. I was a fan of Doctor Who, but I never sat at home thinking, “Oh, god, why am I not in Doctor Who?” That’s not how I work. It’s just how things happened.

You’re one of the few cast members returning for The Huntsman. When do you start shooting that, and have you gotten to read a script yet?

FROST: Yeah, absolutely! There is a great script, and I think we start shooting soon-ish. I think we start in four or five weeks. There’s a lot more for me to do in this film. I really love working with Chris Hemsworth, and the other guys in the last one. I’m really pleased that they’ve invited me back and I get a chance to be Nion again, next to the lovely Chris Hemsworth.

Is there any update on the next Tintin movie, or are you also wondering if and when that will ever get made?

FROST: Yeah. I really hope it goes, but I think Pete [Jackson] has just been really busy with The Hobbit. When he decides what he wants to do next, we’ll either do it or we won’t do it. We had a great time, me and Simon and Toby Jones and Daniel Craig. There’s so much rich fodder in the Tintin universe that it would be a shame to not reprise that.

Obviously, everyone is wondering when you, Simon Pegg and Edgar Wright are going to work together again. And with Edgar making another movie this year, is there any chance that you’ll have a role in that?

FROST: I don’t know. I’ve read the script and it’s fantastic, but I don’t think there’s anything there for me, personally. That’s fine. I like it when the three of us do something. I hate it when Edgar does something on his own. No. We talk about it, all the time, and we have some great ideas. It’s just a case of the three of us actually carving some time out, in the next whenever and doing it. When it happens, we’ll have a bloody good time, and hopefully people will have a good time watching it.

Cuban Fury was such a great, fun movie. Have you been writing a lot recently, or are you just focused on the acting stuff, right now?

FROST: No, not at all. I went through a run of being in movies a lot, so I’ve taken a step back and spent the last year or so writing. I’ve written a couple of films, and a children’s book, and I might be writing a memoir. And then, when people see you again on film, it’s like, “Oh, this guy! We should get him.” It’s about the long game.

Was writing a memoir your idea, or is that something someone asked you to do, and why is now the time to do something like that?

FROST: The older I get, the less I remember. I thought it was important for my son, who’s a little baby, at this point, to be able to have questions answered. Now that I don’t have parents, I can never have those questions answered. There are things about them and me and his mom that he can look at in years and say, “This is my history. This is where I’ve come from.” I thought that was important.

If you could go back a few years to when you were starting out, what advice or guidance would you give yourself, that you wish someone had given you?

FROST: I don’t know. Lose more weight, or something like that. In terms of my career and the way it’s happened, and the fact that I’ve worked so hard over the last 10 years, I think I’ve done it all right, at this point. I’m sure there are wardrobe decisions where I should have said, “You should not wear that in Cuban Fury because you look like a big fucking egg,” but apart from that, no. I’m all right. I don’t regret anything that I’ve turned down, and I don’t regret anything that I’ve done, really. So, I think it would be health based.

How do you feel you’ve changed, as an actor, over the years? Do you have a process that you always use to get ready for a role, or does that always change, based on what the role is?

FROST: I’m sure people would argue this, but I want to be different in everything I do. I don’t think I’ve been the same in anything I’ve done, and I want to keep that up. I don’t see the point of being an actor and doing the same thing, all the time. Where’s the challenge there? In terms of my process, I’ve very easy on set. I often laugh and fuck around, right until the A.D. says, “Action!” I’m not one of those actors who broods around on set in character, at all. That said, if that’s someone else’s process, that’s completely valid. It’s just not mine. If I’m shooting, I will literally work on a script for two hours, before I go on set. And then, I’ll come back and do an hour, have a shower, and then do another hour and a half at night. I make sure I know everyone’s lines, and I know the whole script and where the characters come from. My scripts are always heavily noted. If I can take a director to one side and say, “Do you mind if we try this?,” a few days before, that’s usually a better way of doing it then on the day.

Is there anything you won’t do for comedy, if it gets a laugh and works for the story?

FROST: I don’t know. Yes, probably, but I don’t know. When I was younger, I jumped out of a moving car. I would do anything. Now, being a father and knowing the political state of the world, there are certain things which potentially could be religiously volatile that I would probably avoid, but not much.

Unfinished Business is now playing in theaters.