IT'S A MOD, MOD WORLD OUT THERE—again. More than 30 years after doeeyed gamines like Twiggy and Jean Shrimpton made hip-hugging microminis and skin tight satin shirts fashion imperatives, the look is once more de rigueur. Trend-setting celebs like Julia Roberts and Demi Moore have adopted the mod maquillage of pale skin, smoky eyes and barely there lipstick. Displaying a retro penchant for patent, Elizabeth Hurley, Tabitha Soren and Cindy Crawford have been seen stepping out in go-go boots. And at September's MTV Music Video Awards, Madonna donned a shoulder-length blond fall and black hip-huggers.

Resurfacing on the runways earlier this year, mod was the rage again at last week's spring collections in Milan and among designers such as Gucci's Tom Ford and Manhattan-based Marc Jacobs, whose shiny chartreuse shirts and lean, low-slung trousers epitomize the style. "At this moment, vulgar sex appeal is not interesting," says Jacobs. "There's something sweet and sexy about hip-huggers at the same time." And just as the original Youthquake, which began in Britain and quickly crossed the Atlantic, was a rebellion against the slick greaser look of the '50s, stylemakers say mod's resurgence is an outgrowth of grunge. "It's sleeker, pared down," says designer Anna Sui, a mod fan. "It's the exact opposite of what grunge was."

So omnipresent is the revival that even British pop bands like Blur and Oasis, whose mop tops are reminiscent of the Dave Clark Five, are getting a boost. All of which gives veteran modster Marianne Faithfull—who cheered on the fashions at Sui's fall show—cause to chuckle. "In the '60s, I don't think everybody realized that that was going to be the wave of the future," she says. "Now we see it is."

...The hip-hugger
"It's sexy without being vulgar," says designer Marc Jacobs. But, warns Kathy Kaehler, personal trainer to Meg Ryan, "they're not the choice for big hips."

...The boots
Thanks in part to Nancy Sinatra, boots remain one of mod's most memorable footnotes. Now back in fashion, they can be worn in any length from mid-calf to knee-high. Either way the shinier the better.

...The suit
In the early '60s mod's working-class British boys instituted a strict dress code that required jackets and pants with Italian-style tailoring and a slim cut. Today's menswear designers, including Paul Smith, Tommy Hilfiger and Richard Tyler, have recaptured the look for fall.

...The hair and makeup
The face of mod includes dark, smudged eyes, subtle lips and pale, powdered skin. As for the hair, think Mary Quant's short bob or Marianne Faithfull's long locks. "The bangs are very flat and heavy looking," says Beverly Hills coiffeur Joseph Kendall. "The cut is geometric, but with a little lift."