"If somebody would have said, 'OK, here is the prediction: You're going to meet a man 25 years old and he's going to see being with you and having your three kids as a bonus,' I would have said, 'Keep dreaming,"' the 44-year-old actress says in an interview in Vanity Fair magazine's February issue, on newsstands Jan. 9.
"I think it caught us both by surprise, and particularly him," Moore says of Kutcher, who is now 28. "He was in this real rise of his career just as we met, which for a young man is prime opportunity for heavy-duty play."
The couple were married in September 2005. Moore, whose screen credits include "Bobby," "Ghost" and "Charlie's Angels: Full Throttle," has three daughters from her marriage to Bruce Willis, which ended in 2000.
Kutcher, who starred in TV's "That '70s Show" and in films such as "Dude, Where's My Car?" and "The Guardian," is "really an old soul," Moore says.
"We've teased each other recently about doing 'The Graduate' on Broadway but, you know, historically, real couples being on-screen together never seems to work," she says.
"But a project that we create, that we're maybe more behind-the-scenes? I couldn't think of anything better, because there isn't anybody that I would rather spend my time with."
Any more children in the future?
"Most definitely," she tells the magazine. "Once you hit three, when you're outnumbered, it's really, like, what's the difference between (three or) four or five? For me, the most important thing that I've contributed is my children."