You're gonna need a bigger truck...

Did you take the look of the trolls from the fairy tales or invent them yourself?

The fact there are several types of troll and giving them names, that is my own invention.

Trolls are always depicted differently. There are trolls with three heads, even nine heads in the fairy tales. I had to bring those in because I always loved the three-headed trolls.

I wrote the script and described the trolls as I wanted them. I worked with two artists for a couple of months. One would draw and the other one would mould. We agreed on four basic trolls. Then we would give those elements over to the 3D artist and they would design characters based on that, putting all the details on them and making them look really real. 

How did you decide how the trolls would move?

When it comes to the animation and movement we looked at anything from the T-rex in Jurassic Park and other huge animals to see how the body moves. How weight is distributed.

When it comes to the details on the surface it is mostly nature. Trolls are considered creatures of nature, there is moss, wood, stone, trees growing out of them. 

What was the idea behind turning it into a mock-documentary?

I realised it was going to be a unique way of doing a film like this, a monster movie with a dry sense of humour.

Of course Cloverfield came out in the middle of it but that didn't make a big impact on the film other than it was interesting to see how it did certain things. 

Also they went out of the way to hide the creature as well which wasn't my intent. I loved the way it was done in Jurassic Park where you see the creature when you are supposed to see it. 

You wrote the part of the troll hunter for the comedian Otto Jespersen. The student presenter, Glenn Erland Tosterud, also does stand up and the government bureaucrat and the Polish thief are also played by comics.

I cast comedians to make sure the audience understood that we were going to watch a comedy at heart. For sure in Norway it is considered a very comedic film a lot because these guys are funny on sight basically. You see them and you kind of almost laugh. 

It was a very conscious decision to signal to the audience that even though things are taken dead seriously here, you are allowed to laugh. 

I didn't want to make it a really frightening film. I wanted to make it a film that had a little bit of both, humour, a feeling of horror, but I didn't want to go all the way out in that direction. We kept it relatively innocent on the horrific level. Farting trolls kind of take the edge off something that could be very scary. 

What the troll hunter does is pretty incredible but he seems very disenchanted.

I wanted it to be a portrait of a guy who has a job that he doesn't see as very exciting. I think we can all relate to that, Sometimes we do amazing stuff - as a film maker I experience wonderful things - but sometimes you just focus on doing your every day job and you forget that what you are doing is actually quite amazing to everybody else. 

I feel like I could relate to that and I like that sense of humour, how Bill Murray's character in Ghostbusters is very kind of jaded. 

Also it is a little of the Indiana Jones character who is doing things more because he has to than because he is enjoying it. 

The fate of the characters is left pretty open-ended.

I am hoping that if we do a sequel we can continue where this one leaves off. 

Didn't you have to stand-in for the creatures which are added by computer later?

I had to play the trolls for the actors sometimes. I had to growl and wave my arms and run around. I felt ridiculous but they were so into it. When you are on a film set you are so focused on getting it right.

But of course we'd would laugh sometimes. We had a lot of fun, but they wouldn't laugh at me fortunately. 

The weather could be pretty extreme, filming among the fjords, forests, in "The Wet Valley" and among Norway's tallest mountains

At times the conditions were just wonderful because you would get this kind of rain and it would be just perfect for the mood but when you are doing special effect shots you can't really do a lot of that.

When we were up in the mountains shooting the finale we arrived at the set on Friday and there was no snow anywhere, We shot one big scene outside the cabin, had a weekend off, Monday comes and it was white. We had to start all over again. 

We would sit in the car for four hours just waiting for the fog and the snow to stop. 

Were the mountain scenes particularly hard on the cast because of the freezing temperatures?

The actors were under dressed. We made up all the costumes in August and didn't really think ahead as we should have. 

Of course they had all thermal underwear on but it was very cold. Sometimes they were just running into their trailer, coming out three minutes before the camera was rolling, then right back in. 

Even though he has to kill the trolls when they are a threat do you think the hunter is actually sympathetic towards them?

The troll hunter feels the trolls are not being treated the way they should. I think that is the whole basis for why he allows the documentary team in. 

In the film the idea is they are kept out of sight because of fear of the Norwegians being terrified of their own country basically. 

You have a scene where the real Prime Minister of Norway, Jens Stoltenberg, apparently accidently confirms the existence of trolls. How did you get that?

That is footage from an interview from a press conference he did that we just bought the rights to use. We were fortunate to find in the 20 or something minutes it lasted one spot where he was talking about a gas field in the North Sea that is called The Troll Field. We just edited the sound. 

I've no idea if the Prime Minister has seen it, I hope he has because he is in it, involuntarily I guess.

How has the film been received?

In Norway it has been huge. The most popular film in Norway for a while. It has been a monster success. 

It has been received brilliantly everywhere. I've been invited to show it at festivals in Korea and Israel and places all across the world.

Some seem to find the idea of trolls exotic and I find that interesting. Of course in Norway it is the familiarity with it that is interesting, but it is tweaked in a way they, the Norwegian audience, didn't expect. I think they are finding it a lot of fun to see the folklore being used in a modern way

What are your plans for future feature films?

I have other ideas that I hope to get made. I am working on a few things with American producers for American audiences. I have an idea for a Norwegian follow up film to Troll Hunter. A different type of movie. 

We are talking about a sequel so there is the option for that. Right now the American remake is first up. 

I think they are in the middle of writing the script. If they keep that momentum up they could have it shot next year.

Is it still going to be set in Norway or relocating to the Redwood forests of California?

I think it would be kind of weird. I think they are going to set it in Norway, that is what they are telling us.

They wanted me to write and direct it but I said 'no thank you'. I did feel like it was kind of competing with myself, trying to make it better in a way. I didn't really want to do it. Also I have worked on this movie for a few years now so I am very happy to do something else.