I'm ducking Matt Damon. We're supposed to meet at the Central Park Zoo ticket booth precisely at noon, but I'm not there. I'm thirty feet away, standing behind a huge oak tree, keeping watch.

Cameron Crowe, the director, has urged me to try to get a glimpse of the 41-year-old actor when he doesn't know I'm there. "Matt's fans relate to him as an older brother or a member of the family. And that's how he relates to them," Crowe says, recalling how during the shoot of their new movie, We Bought a Zoo, he liked to do reconnaissance on Damon as he signed autographs and interacted with his public.

The Boston native, who now calls New York home, can be reticent in interviews, reluctant to reveal too much or get too personal. I want to observe him in his natural habitat, and I imagine that my stealth will be rewarded with the kind of unguarded moment that can only be viewed in the wild. As minutes pass, however, and I don't spot him anywhere, a thought looms: This is Jason Bourne I'm hunting—the master of evasion. What if Matt Damon is ducking me?

Stepping into the open, I sort of wave my notebook like a journalistic homing beacon, and suddenly there he is, all smiles. "Hi, I'm Matt," he says, extending a hand. He's in jeans, a gray waffle-y long-sleeve T-shirt, and what look to be brand-new black Puma sneakers. He has a knit cap pulled down to his eyebrows, which makes it easy to notice that his hat and his eyes are exactly the same blue. He's taller than I thought he'd be and exactly a quarter inch taller than the man standing next to him: a gray-haired, bespectacled guy in pleated chinos and a baseball cap.

"This," Damon proclaims, "is my dad....