Scarlett Johansson struts her stuff in cleavage-baring dresses on the red carpet, but in real life, she'd rather remain a mystery.

"I can't stand those articles where people spill their life story," Johansson says in the October issue of InStyle magazine, on newsstands Friday. "After a while I feel like I know more about them than their best friend does — and that's weird. It's better when you don't know everything."

The 21-year-old actress, whose screen credits include "Lost in Translation" and "Match Point," plays a former prostitute in "The Black Dahlia," opposite Hilary Swank and Josh Hartnett.

Johansson says: "Do I ever get nervous about this, right now, being the pinnacle of my career? Yeah, I do. At the end of (filming) every movie I think, `Wow — this is the last one! Nice working with you."'

She's more confident about her hourglass figure. "I'm curvy — I'm never going to be 5'11' and 120 pounds. But I feel lucky to have what I've got."

And, given the chance, she'd like to trade lives with President Bush. "Whose life would I like to step into for the day? The president's. I could probably get some things done in the Oval Office."