Ben Affleck took on a daunting challenge with the role of Jack Ryan in The Sum of All Fears (opening Friday). He knew best-selling author Tom Clancy's famed CIA analyst had already been portrayed by two Hollywood bigshots: Alec Baldwin in The Hunt for Red October and Harrison Ford in Patriot Games and Clear and Present Danger.

"It's very intimidating," admits the 29-year-old actor. "I'm not going to step in there and try to follow in those footsteps — that's madness. You could only disappoint people."

A prequel of sorts, Sum takes Jack Ryan back to his young-rookie days at the CIA. Affleck hopes turning back the clock will dissuade moviegoers from comparing him to his predecessors — though he's not certain the gimmick will sway some fans: "There are going to be people that no matter what — and certainly with me [in the role] — are going to go, 'Well, he's not Harrison Ford.' Or, 'I can only see the Alec Baldwin version.' That's just the way it is. I'd be fooling myself if I thought any different.

"I'm willing to take the hits from the die-hard people," he adds. "I also hope that people give it a shot and give it a chance. I sort of knew that, at the end of the day, this is not a movie that I would have taken if I was somebody who compulsively needed everyone to love him and say he was great. I don't pretend to be Harrison Ford — I'm an actor that got hired to try to do the best job that he could do."