Will Smith in I Am Legend Courtesy of Warner Bros.

Smith confesses to being a little unnerved by the conversation, but was even more alarmed when he learned about the inevitability of a "slate wiper," a term coined for a virus that will destroy humanity.

"We saw a war room. They have a wall there, and it's all television monitors with 100 people that sit in front of all of the monitors all day long. It's CNN and the BBC and Al Jazeera. And they have people on standby around the world that respond to outbreaks," the actor reports.

Learning about the spread of viruses and the containment of a major pandemic was vital not only for the plot, but for informing Smith about his character. He is first and foremost a doctor and so spends much of his time trying to understand the plague and why it has transformed everyone he has encountered other than himself. But, according to Smith, Neville is a doctor-warrior with a savior complex.

"On the cover of Time magazine before everything happened," the actor says, explaining the movie's plot, "there was Robert Neville's picture, and it said: 'Savior. Soldier. Scientist.' And he was supposed to be the one that stopped it. He was the foremost epidemiologist. Manhattan was his site. And he lost it. And it got out and he lost his wife and daughter and essentially he lost mankind. He has to bring it back. He has the Time magazine taped on the refrigerator and where it says savior he's scribbled in a question mark. And every day he tries to get a step closer to finding the cure, with the deepest desire to reverse it all. But every day they get closer and closer to killing him. So essentially it's about [whether or not] he finds the cure before they find him."

A TEST OF CHARACTER

Smith, Hollywood's most bankable and powerful star, knows that I Am Legend is probably his biggest test to date. He will have to hold his own as the only actor on screen for long periods of time in a character drama that could be overwhelmed by kaleidoscope of technical special effects.

"I would say this is probably the scariest one I've done since probably Ali. And Ali was a terrifying undertaking," the actor confesses. "But with this film, we were trying to break genre. And to make a film like this, we want to do something new. I am by myself with a dog for the first 60 pages."

Smith has realized that for this role he had to subdue the Fresh Prince/Bruckheimer–Bad Boys persona and all the snarky one-liners: "Comedy comes from how perfectly you can set the dramatic situation. It is killing me to restrain myself."