It's Paris Hilton's favorite recipe: Take two fabulously wealthy heiresses, strip them of their credit cards and couture, mix vigorously with airhead humor, and voilà -- you've cooked up a heapin' helpin' of "The Simple Life."
At first glance, Hilary and Haylie Duff now seem to be serving up laughs at the expense of Hilton's reality show misadventures. In "Material Girls," opening Friday, the Duffs are down-on-their luck celebutantes who lose all their bejeweled designer goodies and couture when Daddy's cosmetics empire gets caught in a scandal.
Suddenly they have to figure out how to take a bus -- gulp! -- just like the rest of us. "Friends don't let friends take public transportation," Hilary tells Haylie after they've been forced to live like common folks.
Of course, the Duff sisters deny that they're parodying Paris and Nicole Richie (or even Paris and Nicky Hilton). And unlike those other young, club-hopping celebs, Hilary and Haylie are famous for something other than, well, just being famous.
"I think everyone knows some 'Material Girls,"' Haylie tells reporters, sitting side-by-side with her sister at a New York City hotel, just days before their film opens.
The Duff sisters -- who tend to finish each other's sentences, shoot knowing glances and giggle compulsively at each other's jokes -- try harder than most stars their age to avoid controversy and embarrassing pictures of themselves showing up in celebrity magazines.
"I sometimes open up one of these magazines and go 'Wow!' says 18-year-old Hilary. "I know privacy is an issue, but you know where you want to go if you want to be seen, and you know where to go if you don't."
Sure, Haylie, 21, had her spat with Hilton two years ago, after they both recorded the same song -- "Screwed" -- and that's how Haylie felt when Hilton's version was leaked on Web sites before her debut album came out.
And, of course, Hilary's rivalry with Lindsay Lohan seems to be ongoing, after their well-publicized catfight over pop singer Aaron Carter, whom they both dated. That spilled out when an uninvited Lindsay was asked to leave the premiere party for Duff's "Cheaper by the Dozen," and they've been sniping at each other ever since.
But the Duff sisters are already both savvy show business veterans. Hilary is a veritable one-woman industry, releasing "Material Girls" amid the launch of a new album in November and a lifestyle company modeled on the hugely successful Mary-Kate and Ashley brand.
Hilary's "With Love," a fragrance by Elizabeth Arden, will be launched in the coming weeks, along with her 'tween fashion collection, "Stuff by Hilary Duff."
Even the lesser-known Haylie can hardly be compared to one of the many do-little celebrity siblings. She won a 2005 Teen choice award in the "Breakout Performance" category for her work in "Napoleon Dynamite." Her role as the young and pregnant Sandy Jameson on "7th Heaven" got raves. And she recently made her Broadway debut as Amber Von Tussle in "Hairspray."
Still, as they promote "Material Girls," the Duffs are throwing some crumbs to showbiz gossips, laughing about how Hilary's boyfriend, Joel Madden of Good Charlotte, and his twin brother, Benji, came to make cameos in the film. It was a last-minute thing, they said, after director Martha Coolidge told them that they needed to cast two tough-looking car thieves.