They'll host SNL   Mary-Kate and Ashley Olsen will host "Saturday Night Live" at 10:30 p.m. Saturday on Channel 4.

LOS ANGELES - Sometimes two of a kind beats a "Full House." Mary-Kate and Ashley Olsen proved that by topping their childhood stint on that saccharin sitcom by starting a billion-dollar enterprise of direct-to-video movies, a little-girl fashion line, and assorted books, dolls, trinkets and doodads. Nearing their 18th birthdays, the two starlets are about to see whether their legions of fans are outgrowing them or are planning to follow them into adulthood. "New York Minute," which opened last weekend, is the first feature film from the duo since 1995's "It Takes Two," when they were 9. If it's a big hit, "New York Minute" could show Hollywood that the Olsen twins are ticket-selling powerhouses like fellow teen stars Lindsay Lohan and Hilary Duff - but a catastrophic flop could relegate them to the uncool, forgotten-in-the-toy-box status of Barney the purple dinosaur or the Teletubbies. The girls, who have been famous since they were 9 months old, have an almost blasé attitude about their fame, their future, their fortune and their wholesome image. They say they don't calculate how to appeal to fans. "We wouldn't be successful if our fans didn't like what we were doing," Ashley said. She and her sister are worth an estimated $150 million each. The twins recognized that "New York Minute" was a pivotal project for them - which is why they front-loaded the movie with comedians aimed at young adults: Eugene Levy, Andy Richter and Darrell Hammond. For all their success, the Olsen twins still have a stigma to overcome. Although some lecherous male fans have made sport of counting down the days until they turn 18 (on June 13), Mary-Kate and Ashley are still regarded by many as the realm of goofy little kids. Consider Angelina Gaspar, a 20-year-old from Visalia, Calif., who traveled two hours to Los Angeles on April 29 to see Mary-Kate and Ashley get a star on the Hollywood Walk of Fame: "I get made fun of, but you know what? That's fine. Laugh all you want. At work, I'm the laughingstock of the store right now because I'm here. But you know what? When I come back I'm going to have pictures; I'm going to have an autograph, hopefully," said Gaspar, who wore a T-shirt featuring the Olsen sisters from about age 10. Gaspar said she plans to see "New York Minute" about 10 times in the theater. Robert Thorne, the entertainment lawyer who founded the Olsens' Dualstar Entertainment company and helped create the "Mary-Kate and Ashley" brand of products, dismissed the notion that they have something left to prove. "Whatever naysayers are out there exist for any celebrity," he said. The publicity push for "New York Minute" has given the Olsen twins a sample of the gossip that they have been relatively immune to for years because of their under-the-radar direct-to-video careers. In Touch Weekly magazine recently questioned whether the ultrapetite twins had eating disorders, and tabloids routinely feature them with their respective boyfriends (Ashley is dating 20-year-old Columbia University football star Matt Kaplan, while Mary-Kate is romantically linked to 21-year-old David Katzenberg, son of DreamWorks studio co-founder Jeffrey Katzenberg). Will the twins someday try to court new guy fans like other young actresses, posing in skimpy outfits in magazines? "I doubt it," said lawyer Thorne. "I mean, the answer to that is no." Even if "New York Minute" is a hit, the teens will be forced to confront another question: How long do they continue to work as a pair? Will they be making twin movies for rest of their careers? They leave it open-ended. "We have an idea of what we want to do and whether it's acting separately or producing together, or one directing and one acting," Mary-Kate said. "I think in some way we'll always be connected. We're sisters, a team, regardless of work or not." Then there is the question of their name: Some news reports have said the pair issued an edict that they not be referred to as "the Olsen Twins." It's not true, they said, although they prefer that people use their first names. "It's nice when somebody calls me by my name and doesn't say, 'Hey, you're an Olsen twin,' " Ashley said. "It's better when they say, 'Hey, are you Mary-Kate or Ashley?' " They'll host SNL Mary-Kate and Ashley Olsen will host "Saturday Night Live" at 10:30 p.m. Saturday on Channel 4.