Fashionistas were tittering when socialite and investor Julie Macklowe got dissed by the Olsen twins at Fashion Week. Macklowe — who heads skin-care line vbeauté (“She wants to be the Tory Burch of beauty,” sniffed one fashion insider) — was looking to pump her brand with some intrepid guerrilla marketing. “She was carrying samples in her bag,” a spy said, “and was trying to shove them into celebrities’ hands at shows, so they’d be photographed with her products.” But when Macklowe, the wife of real-estate scion Billy Macklowe, tried the technique at the J. Mendel show on Wednesday, Mary-Kate and Ashley were less than enthusiastic. “They said, ‘Um, send this to [p.r. reps] Wolf-Kasteler,’ ”another spy reports. Macklowe told us, “I am a big fan of [the Olsens’ line] The Row, so I offered them an ‘It Kit,’ which they requested we send to their publicist. I’m flattered by the ‘Tory Burch of Beauty’ reference . . . to have half of Tory’s success would be fantastic!” Work it, girl.