I Am Legend is the new big budget adaptation of Richard Matheson’s 1956 novel, which has previously been filmed as The Last Man on Earth in 1964 and as The Omega Man in 1971. The film’s star Will Smith spoke to David Grove about what it's like to play the last man alive.

What intrigued you about Richard Matheson’s novel?

The basic idea, the idea of a man being the only man left on earth, is terrifying. As an actor, playing a character like that is a major challenge. I didn’t know how challenging it would be until we started filming and I realised that I couldn’t rely on all of the tricks and mannerisms I’d used in past films. Since I’m basically the only character in the film, at least the only character who lives and breathes like a normal human being, there’s no one else to play off, no one-liners I can deliver to lighten a scene.

The idea is terrifying, not just in terms of my character, Robert Neville, but as an actor. It might be the most challenging role I’ve ever done. Ali was a great challenge because of the physical part of playing Muhammad Ali, who’s so well-known, but I Am Legend was a great challenge in terms of having to rely on emotions to create this character. I like to laugh, and people like me to laugh and have fun in my films, but this isn’t that kind of film. Not at all.

You’ve been with this project for a long time…

Probably over a decade. I was going to make the film a few years ago, around 2002, but then 28 Days Later came out and kind of stole our thunder. This film is totally different from 28 Days Later, and I think our story is much stronger. But it had a similar theme so we put it off, and me and Michael Bay, who was going to direct I Am Legend, went and did Bad Boys II.

Looking back, I’m glad we didn’t make the film then, because I don’t think that was the right time. I’m a producer as well, and as a producer I like to really nurture projects, give them time to develop until they’re ready to shoot, like what I’m doing with Tonight He Comes.

How much input did you have in terms of the film’s story?

I was involved with this project for a long time, and I had a lot of ideas about what kind of film I’d be interested in making. I liked the original script that had been written, and then I met with Francis Lawrence and we talked about who Robert Neville should be in the film, specifically that the film should be a real character study instead of a plot-driven horror film.

I didn’t want to rely on big special effects, but instead I wanted to test myself by having the film rest entirely on my shoulders. I wanted the horror to exist in Robert Neville’s mind.

You did a lot of research for the film?

Yes, in terms of the virology element of the story, a lot of research. I spent many hours with the Center for Disease Control, learning about viruses and how they spread and what they can do to a civilization. I also spoke to different virologists and asked them about the premise of our film, where a virus wipes out the population, and how that could possibly happen. I play a brilliant scientist in the film and I really wanted to be well-versed in the subject matter.

You see I Am Legend as more of a character film than a genre movie?

Yes, absolutely. Francis Lawrence wanted to create an interesting character study within the body of a big action movie. I think an ‘arthouse character film’ is what we talked about doing, if we could get away with doing that.

Robert Neville is the last man on earth, and his world is very contained, very small, and that’s where the tension builds in the film. He can only go out during the day, so he only has a few hours to get what he needs and hopefully bring himself closer to finding a cure, because finding a cure for the disease is what keeps him going. This movie is all about Robert Neville and showing how he stays alive, why he stays alive, and what he does during the day.

It’s hard, and I think this was the biggest challenge in bringing the story to the screen, because there’s no real villain in the story, just Neville alone with his own thoughts. The creatures vanish during the day, and at night, Neville keeps himself barricaded in his home so there’s not a lot of direct conflict there. Neville’s enemies are isolation, loneliness, paranoia. Neville’s only real companion in the film is his dog.

How would you describe the monsters in the film?

They’re somewhat like Neville in that they’re survivors. They’re human-like mutants. They have human qualities, which makes Neville believe that he can possibly find a cure, but they’re also bloodthirsty creatures. They want to kill Neville, and so Neville tries to kill them as well, to keep them away from him while he tries to get closer to finding a cure.

Instead of the infected being vampires, we decided that it would be more interesting to show them as being infected by a virus that changes them in real medical ways. In that way, the film is sort of a metaphor for AIDS and other real-life viruses that exist today. They look like real people in the film, which I think makes them scarier.

Were you a fan of The Omega Man?

I actually really liked The Omega Man. I saw that film when I was just a little kid and it stayed with me. It’s the kind of movie that you can watch over and over again, and I’d seen it many times before I started work on this film.

I thought Charlton Heston gave a great performance in that film, and I thought the film did a great job in terms of the Neville character and how someone like that really would survive from day to day. It also had some social commentary in it which I found really interesting. It’s one of my favorite genre movies.

How does the new adaptation compare?

I think it’s a very current film, very modern. There’s a lot of stuff in the film about genetic engineering, which is how the virus is created in the film. There’s a lot of research going on today where different strains and viruses are being mixed together in the hope of finding cures for diseases. In the film, the virus is created through the alteration of blood cells where the cells are mixed with the wrong parts of a virus that creates this super-virus that wipes out the population.

Diseases and viruses are a threat to the world today, much more than they were when the previous films were made, and I think this film shows a terrifying possible future vision of that. The infected monsters have a disease. They’re not vampires, or ghouls that crawl out of the earth. They’re victims of a disease for which there is no cure.

What keeps Neville going in the midst of so much hopelessness? Do you think you would make the same decisions if you were in the same situation?

I think Neville realises that he has a greater responsibility than just keeping himself alive. He’s the last man on earth, although in the film Neville actually theorises that there’s probably other survivors out there. In terms of his depression and loneliness, I think he compartmentalises all of that, tries to block it out, and thinks about the family he lost and tries to remember the good parts of his former life. He’s the only hope for mankind, and he realises that, although I think he also wonders “Why Me?”

I don’t know what I would do in that situation. That’s the point of the film. We ask the audience to put themselves in Robert Neville’s shoes.

I Am Legend is on general release in cinemas in the UK and US.

Click here to view a clip from the movie.