Actress Drew Barrymore poses during a news conference announcing Barrymore as CoverGirl's newest model and spokeswoman, on April 11, 2007, in Beverly Hills, Calif.

She was born with her acting¹ family's classic beauty, but Drew Barrymore credits her fun-loving approach to life for her No. 1 spot on People magazine's annual "100 Most Beautiful People" list.

"I just think happiness is what makes you pretty. Period," she tells the magazine. "Happy people are beautiful. They become like a mirror and they reflect that happiness."

Barrymore, 32, graces the cover of the issue that hits newsstands Friday. It's her fourth time on the list, but first as cover girl.

Making the cover "made my peacock feathers shine in the golden-hour light and extend to the heavens," says Barrymore, who stars in the upcoming Warner Bros. film "Lucky You," opposite Eric Bana.

Inside, she weighs in on a host of beauty-related topics. Her beauty rules for dating? "The only fundamental rule for me is to just be yourself," she says. "Let your freak-flag fly, and if someone doesn't get you, move on."

Barrymore is one of 11 celebrities² - including Eva Longoria and the three Jessicas (Simpson, Alba and Biel) - photographed for the issue without makeup³.

"I find that men, in my past, have preferred me without it," Biel, 25, says of makeup.

Among others on the "Beautiful People" list: Brad Pitt, Angelina Jolie, George Clooney, Oprah Winfrey, Alicia Keys, Leonardo DiCaprio, Nicole Kidman, Jennifer Garner⁴, Scarlett Johansson, Matthew McConaughey, Jennifer Aniston, Reese Witherspoon, Halle Berry, Julia Roberts and Jennifer Lopez.