AGES: Alexandra (left), 17, and Theodora, 19
WHY THEY LOOK SO FAMILIAR: Dad is Rolling Stone Keith Richards and Mom is '70s supermodel Patti Hansen.
EDUCATION: Alex is a high school senior. Theo graduated two years ago.
BREAD & BUTTER: Both are models who have walked the runway for Tommy Hilfiger.
ALEX'S RULES: "I only trust myself to cut my hair.... I never have dark eyes and dark lips. So one night I will have red lips, the next, smoky eyes."
THEO'S RULES: "I never use the same two shampoos and conditioner. I keep mixing it up.... No full-coverage makeup. When you hug people, it gets on them, on the phone. It's so horrible."
FAVE BEAUTY FLASHBACK: "When we were really little we had this plastic blow-dryer, fake lipsticks and polish," recalls Alex. "Theodora was drying my hair, getting it stuck and twisted, telling me, 'You look dazzling.' "
WHY SHE LOOKS SO FAMILIAR: Her mother is Isabella Rossellini (her dad is Jon Wiedemann, an ex-model).
EDUCATION: A college sophomore on sabbatical from Boston University.
BREAD & BUTTER: Works as a model in Milan so she can "make money and be independent."
MUST-HAVES: "Sunscreen, because I am super-fair and burn in three minutes.... I'm very badly addicted to La Belle lip balm. I couldn't do without it.... Maybelline mascara is the cheapest and the best."
BIGGEST BLUNDER: "I put mayonnaise in my hair once and I swear I had oily hair for five years."
WHAT SHE WON'T DO: "Can you tell I don't take care of my hands and feet at all?" she asks. "My feet are beyond help. And anytime I do facials I break out. What's the point of paying someone to give me pimples?"
WHY SHE LOOKS SO FAMILIAR: Her dad is Kevin Costner.
EDUCATION: A high school senior.
EXTRACURRICULARS: Basketball, flag football and Miss Golden Globes 2004.
MUSTHAVES: "Kiehl's lip balm. I put it on my cuticles and under my eyes too." And Neutrogena Body Wash—"the smell reminds me of my mom [Cindy Silva]."
WHAT'S NEXT: After college, where she plans to study music, "a singing career. It's the one thing that I've always been sure about in my life." She already has performed at an Aspen club.
THE PROUD POP: "I've seen her on a field yelling, with cut-up knees," says Costner. "Then to see her dripping in diamonds, I thought, 'God, she really does kind of have it.' I'm really proud of her."
Lydia HEARST SHAW
WHY SHE LOOKS SO FAMILIAR: She is the daughter of media empire heiress and actress Patty Hearst and Hearst Corp. security chief Bernard Shaw.
BUSY, BUSY, BUSY: She's a college sophomore studying communications and a Ford model who recently nabbed the cover of Italian Vogue.
FOR CLASSROOM OR CATWALK: "If I wake up with puffy eyes, I put a cold soda can underneath them and it makes the puffiness go down.... I carry a little tub of Vaseline in my purse. It takes off eye makeup and gets rid of chapped lips.... I hardly ever break out, but if I do, Mario Badescu drying lotion is a quick fix."
WISE WORDS FROM MOM: "If you are nasty, that will shine through," says Patty. "I always taught her, pretty is as pretty does—and to wash off her makeup before bed, but she doesn't always do that one."