"The first time I ever saw her, I didn't know what her name was or who she was," Kutcher, 25, said, discussing the May-December romance for the first time.
"I sat and talked to her for a half an hour, not having the slightest idea that I was sitting with a famous human being," he said of his 41-year-old girlfriend.
The couple first created a media frenzy when Kutcher escorted Moore and her daughters, Rumer, 15, Scout, 11, and Tallulah, 9, to the premiere of Moore's film, "Charlie's Angels 2."
Eight months later, Kutcher and Moore are still together, despite the public scrutiny of their relationship.
"Man, they should write a handbook for it because I don't have the slightest idea," he said of handling the media attention.