BEN Affleck seems to have it all. By the age of 30, he's won an Oscar, made millions from his hit films and now he's half of the hottest Hollywood celebrity couple, dating actress and singer Jennifer Lopez.

He's set for even more success, after winning the part of CIA agent Jack Ryan in The Sum Of All Fears.

The film is the fourth screen adventure for the character, created by Tom Clancy, and brought to life by Alec Baldwin in The Hunt for Red October and Harrison Ford in Patriot Games and Clear and Present Danger.

This time the CIA analyst isn't a wily veteran as 60-year-old Ford depicted him, but an awkward new recruit who must face up to a nuclear threat by terrorists wanting to draw America and Russia into war.

"We've taken the character back where he has only been at the CIA for a short time. This makes him a very different character from what Alec or Harrison created," says Affleck, who was given the chance to play Ryan after Ford dropped out.

Director Phil Alden Robinson had to have the script rewritten to fit with the younger actor, but he believes the more naive character will appeal to audiences.

"In a movie like this I think it's so much more refreshing to see a young guy who doesn't quite know his way around and isn't experienced with danger having to deal with this situation."

And Affleck agrees that the new depiction should be a hit. "Jack's not James Bond and I like that," he says. "I think this is a smart summer movie for adults."

But he believes that the film does take several chances. "It's a risk starting this character at the beginning and it's a risk to depict this kind of terrorist plot."

Shot before the September 11 attacks, what was made as a political thriller gained a new resonance after the destruction of the World Trade towers.

"Ironically we thought the biggest hurdle in terms of promoting the movie would be trying to get people not to say, 'This is too far fetched'," he says. "After what happened on 9/11 that's tragically not an issue at all. The movie changed without changing a frame."

The film depicts a nuclear device going off at a packed Baltimore stadium, but Robinson didn't dwell on depicting the carnage, much of which is implied instead, something which Affleck believes was the right approach.

"Fortunately I think Phil shot it in a way that's not gratuitous," he says. "It's realistic but respectful. This is not like a big disaster for the sake of eye candy. It's done in a way that tries to imagine what it would really be like.

"Everyone should find this disturbing. Violence in movies should disturb you, it shouldn't be done just to make a big splash. That may be one of the transitions we've made, in that we no longer look at violence in such a flip way. This movie asks you to look at it in a real way."