Katherine Heigl of WB's Roswell says she has the power of prayer to thank for her curvaceous body.

"When I was 13, I was flat as a board and totally unhappy about it," the 21-year-old actress tells Maxim. "I would write in my diary every day, 'Oh, if I could just have a B cup by summer!' I actually prayed for big boobs. So I developed at about 14, and then I was 15, 16, 17, and they kept going."

Ironically, the top-heavy Heigl is now expressing regrets about agreeing to wear only a bra and jeans for a scene in the upcoming movie 100 Girls. "I'm leaning over this guy and shaking him, and I didn't realize exactly what they do when you're moving around a lot," she says. "If they were fake it'd probably look better."

Hard as it is to imagine, the blond bombshell has yet to find the man of her dreams. She says she'd ideally like an older man who dresses in khaki pants, T-shirts and baseball caps. (David Letterman, perhaps?)

"Guys are kind of retarded until they're about 30," Heigl explains. "I've been interested in a man who was 35, but he didn't act 35, you know? Like, I don't think I could really be interested in a 35-year-old Wall Street type. But I do relate to older men better, because it's easier to connect with someone who's a little older and wiser."