Will Smith does not look like a man with worries. He is sitting in a private room at his favourite Japanese restaurant in downtown New York. His bodyguards are outside, there’s a constant flow of sushi and the streets of Manhattan are lined with billboards advertising I, Robot, his latest and most ambitious attempt yet at a summer blockbuster. But behind the wide smile, the 6ft 2in Smith is not as confident as he appears to be.

“I’m more nervous than I’ve ever been about any movie,” he admits in his deep voice. “I, Robot is almost like a small art film wrapped up as a big summer movie. That’s how we approached it. So I’m definitely nervous.

“But I love the film. I think Ali is the best performance I’ve ever given, and I think Enemy of the State is the best all-round movie I’ve made — but I like I, Robot more than both of those. It’s the movie I’ve been threatening to make my whole career.”

Smith always talks a good film, but there’s no question that it is time that he delivered one. Since his Oscar-nominated title performance in 2001’s Ali, he’s been seen only in two lacklustre, if profitable, sequels, Men in Black II and Bad Boys II. They did nothing to alter the perception that he is more interested in maintaining his high profile and reported $20m-a-movie salary than he is in applying his undoubted talent to more substantial roles. After all, this is the man who turned down the chance to play Neo in The Matrix.

“I didn’t get it when I read it,” shrugs Smith. “It’s a hard movie to pitch. You know: ‘Everybody lives inside a computer.’ It was only when I saw it that I really got it.

“But every so often you see a performance you know you couldn’t have given — and Keanu was brilliant as Neo. It was his role. I would have ruined the movie. I would have been trying to force every moment.”

His wife, the actor and singer Jada Pinkett Smith, did appear in the second and third instalments of The Matrix, and a typically genial Smith hung around Sydney, searching in vain for a barber who knew how to cut his hair, while she was working on them.

Perhaps the fact that he passed on The Matrix contributed to his decision to take I, Robot, for which he is also an executive producer. ()

Loosely based on a series of Isaac Asimov short stories, I, Robot is set in Chicago in 2035. Robots are nannies, and deliver pizza and the post far more efficiently than humans can. Smith plays a technophobe detective who loathes them and suspects that a rogue robot has started killing humans. “My character is essentially a racist,” says Smith, who’s dressed all in black, with diamond studs in his ears. “When you go back and watch the performance from that point of view, you’ll see so many little things we put in to emphasise that.”

The film is more complex than most big summer movies, despite some outrageous product placement and the necessary reliance on computer-generated images. There are a few jabs at George W Bush-speak, and there’s a Bill Gates-esque character whose corporation seems to run the world. The biggest risk, though, is that it gives us few of Smith’s trademark one-liners and little of his easy charm. It’s as downbeat a performance as he’s given.

“He’s miserable and he’s a luddite,” notes Smith of his character. “That’s a big gamble for a movie like this.”

Not only that, but science fiction isn’t a genre that black actors are associated with. “It’s weird, isn’t it? No sci-fi, no horror. I think that, artistically, black people in America tend to gravitate to more realistic movies, or comedies.”

Of course, Smith, like Denzel Washington, is that rare black actor who can induce colour blindness in American audiences. His biggest hits, Independence Day and Men in Black, made more than $1 billion worldwide, while most of his contemporaries’ films — Ice Cube’s Barbershop series, for example — rarely cross over to white audiences anywhere.