X-Files actress Gillian Anderson has come a long way since hunting down aliens and the paranormal in her role as Scully. Her perfomance in Bleak House was without fault and now the flamed-haired actress has turned her attentions to political thriller The Last King Of Scotland. She plays a small but perfectly formed role as Sarah Merrit who has a romoantic involvement with on-screen character Garrigan played by James MvAvoy.

The Last King Of Scotland sees handsome young doctor, Garrigan (James McAvoy) arriving in 1970’s Uganda - hoping for fun, sun and to lend a helping hand but he finds himself instead on a shocking ride into the darkest realm on earth: the human heart.

After being called to the scene of a bizarre accident he impresses ruthless dictator Idi Amin (Forest Whittaker) who offers him an unlikely job.

Here Gillian Anderson speaks exclusively to the Mail Online in a Q & A about the film:

What was your knowledge of Idi Amin before doing the film?
I had seen Barbet Schroeder's documentary, so I had seen that version and I find that such a brilliant documentary. It's very difficult when you've seen the documentary and you've formulated in your mind what might be fact or fiction.
We have a tendency to believe a documentary more than we do (a fictional film). Some of the events and scenes parallel what takes place in the documentary.
Also, the script stands alone and has a different take on events. I tried to come to it as neutrally as possible and see it as a film in a way that they are intending to present it today - an entertaining thriller.
I decidedly didn't read Giles Foden's novel because I was afraid that, with such a small character, I'd get too wrapped up in what was there and what wasn't there... I thought, it's just going to be the script for me.

Do you think it's fair that the film humanises him?
I have a very hard time with that because there are certain statistics that are really hard to ignore! Even if one's argument is, "Oh well, he must've had Syphilis and therefore been under the influence of the illness", I don't know.
If we're just talking about the despotism and the committing of the atrocities, I don't know if there's ever any excuse for that, no matter how funny, or how human, or the influence of the rest of the world on creating that particular character. A doesn't necessarily equal Z, you know? That's a tricky one!

How did Kevin approach you about it taking quite a small role?
It was a situation that started with casting directors and them thinking it was a good idea and then trying to convince Kevin it was a good idea, or that I might be put in the mix.
Oddly, when I met Kevin for the first time, I had just come back from Uganda. My ex-husband was doing some work over there and I'd been a few times, so it was very easy to talk about my own experiences and personal knowledge, which is very, very small.
The character felt very familiar to me. I felt like I'd met her before, I'd met people like that in different countries in Africa, British women who'd gone out... There was a particular flavour of women that made that type of lifestyle, and gave themselves to it and what that does to the psyche. I felt I like I understood that.

Sarah, your character, is very interesting because had she had the affair with Nicholas she might have prevented all the terror that was to come.
Well terrible things would've happened they just wouldn't have happened to him! Sarah and Nicholas are obviously in completely different stages in their lives when they meet and I always had a bit of difficulty with that part of the story.
I think it threatens to draw the audience away from him being more callous about women and relationships in general. But then it also sets up his character and naiveté... This young Scottish lad coming to Africa, etc. She's been there for a decade.
I think she in a very powerless place – in a commitment to a partnership with somebody, doing good and with what you witness on a daily basis must have a huge toll on everything - on one's belief system, on one's stamina, on one's view on life and what life is all about.

Are we really making a difference or are we just, as they say, just, "Skimming the surface of the ocean"?
After being involved in that kind of community like what you see in the film; it's a lonely existence, it's a choice but it's a lonely existence.
I’ve got friends in different countries in Africa who have chosen to do similar things and they get regular visitors, regular people coming and staying a couple of weeks, so they get the outlet and they also come to England on a regular basis.
But I got the sense that it was quite a different scenario for Sarah, it was really very solitary.
Anything that comes in from the outside world that smells of freedom and lightness and fresh perspective, it must be tantalizing.
I think she's quite sad at that stage of her life, quite lonely and sad. She believes very strongly in what she's doing but I think that people can see the sadness. I noticed it for the first time when I saw the film.

What do you think the film means to Ugandan people?
It's great that a movie has come in to Uganda, but it's about one of the worst subjects in their history.
There are also a lot of people who were alive then who are alive now so I think of it in a very positive light, but it is really mixed.
He was such a strong force and such a powerful leader that that is the memory that they are left with and from what I understand there wasn't a structure in Uganda at all with filmmaking, and the fact that the producers and Kevin Macdonald chose to use local Ugandans as a good portion of the film crew was a risky thing for them to do.
People have gone to school for years to do sound and lighting... And not only in that respect but just in the extra time they then took not only in the educating but also in the maintenance moving forward, but from what I understand it bolstered the film.
My concern at the time was - here we come in and we run around and we create work and potential, and then we are gone and then there is a negative impact on whole communities.
But it is a tricky argument because there is the other side of it we stayed we employed a lot of people during that time and that may be some of the people involved may go on to find work in other parts of the industry.
Also the communities that where helped, there was lot of generosity from the crews and the producers to the communities and that is always a good thing.
I do know that there is a filmmaker, an Indian filmmaker, who started a film school out there.

What was it like in Jinja where you shot your scenes?
It was in a mixture of corn and maize, or tea plantations but it was in a small village half an hour, forty minutes outside of Kampala and the road between Kampala and Jinja has to be one of the most dangerous roads in the world.

Is that just because it is so busy?
Well yes, part of it is because there is just so much traffic on it and there are a lot of buses that go down it, and their axles aren't right so the wheels are pointing this way but the bus is going that way.
There is no speed limit, and if there is an accident they could be on the side of the road for days before anyone pays them any attention ' there are constant accidents. You would always see accidents everyday.
One day in the first couple of days of shooting, they actually saw a body on one side of the road and the head on the other side of the road on day one of going to shooting, that's just how it is.
Then in the village is what we refer to as grass and mud huts, and they get there water from the well and there is lots of children running around lots of very skinny dogs.
And you drive by these communities the children wave with there beautiful big smiles and they are incredibly open and they take you in if your car broke down and you needed somewhere to sleep.
And to them a big film crew coming in with catering truck and plates full, these huge things full of food.
It was the hardest thing for me to see at times some of the people being used as extras may not have eaten very much for days, and there is a huge tub full of chicken wings that the crew is eating or not eating.
I found that really hard, and I just wanted to give them away to the locals.

Did it help with the immersing yourself into the film and the character?
Absolutely, any time that I have to do something in the real place it is better where there is as much sensory help as possible. I certainly work better that way when my surroundings are accurate to the situation, it is just different, the chemicals in your entire body change than if you are doing it on a set somewhere or doing it on a backdrop.

How did you find Kevin Macdonald as director, coming from a documentary background?
I adore him, I found him unbelievably calm, and unruffled. I mean things went wrong all the time and everyday there was a huge drama.
Whether it was the day that we were shooting the exodus, the Asian exodus, where three people showed up out of two thousand, and we couldn't shoot anything.
This is a massive day of shooting and filming and buses and everything, and we had to wait whilst people went off and gathered as many of the Asian community as they could to be used as extras and we ended up with three thousand instead of two thousand, or when we were shooting that scene with the cow on the side of the road and we were trying to keep that cow tied down humanely.

That scene seems stunning how was it coordinated?
Oh my God there was just so much going on, between the extras and the animal. Trying to keep the cow down, you had to keep tying the horn down to a post in the ground, but it would pull it up every single time, and you’d have to stop filming and tie it back down again.
Those horns, you don’t want to be within ten feet of them, and it’s a complex scene with a lot of people and a lot of extras and then it started to rain.
It rained through probably forty five minutes, it poured torrentially which was fine and everyone went undercover.
I was sitting in a car staying dry and you could see peoples feet sticking out from under all of the tarps, with the camera equipment, keeping it dry. And then on a normal situation on a normal back-lot or something you deal with that and you dry things off and it takes time anyway, but because of the ochre earth it was a completely different colour you had gone from that reddish earth to a deep dark brown and there was no way to make it match and you had to scrap the day go away and shoot it another dry day.
It's an intense and very long scene to have to interrupt and re-do. That kind of stuff was happening every single day for them, and the fact that Kevin was able to maintain his cool throughout it and really just genuinely lovely with people and with the crew and with all the Ugandans.

How about James McAvoy - he's a startling presence who seems to have come from nowhere?
I know, I know I'm just amazed at his energy, that’s what I find most remarkable about him is that he seems to have a never ending source of energy.
And all the stuff that he did, playing football with the kids and carrying them it comes from him, it comes from his ability to just completely revel in the moment.
There is nothing stifled about him, just falls through natural loops and that’s great.