Fashion revisits the ’50s and ’60s this year, but this time it’s not just another spin on the retro cycle. Something about these styles is hitting home, and Hollywood is at least partly responsible.

The key piece is the Mod ’60s, the cotton sundress, often strapless, in bright cotton prints, sometimes with a ribbon tied at the waist. You see them all over town, worn by young girls to parties, weddings and every special occasion.

They fit right in with other popular ’50s favorites — capri pants, little cardigan sweaters, flip-flops — and some of the newest trends such as giant floral prints, polka dots, trims such as scalloped edges, the color pink and a renewed interest in the natural waistline, as opposed to the hips.

And it includes miniskirt — already strong — and little tailored jackets and coats that will appear on the runway for fall.

Recent movies are packed with such clothes, and while at least one of these films criticizes the era, most are comedies.

The films “Legally Blonde 2: Red, White & Blonde” and “Down with Love,” which attempts to capture the old Doris Day-Rock Hudson magic, have a grand romp with pillbox hats, pink tweed suits, pearls, white gloves, short skirts, go-go boots and all clothes reminiscent of the polished styles of Day and Jackie Kennedy.

Charles Nolan, designer for Anne Klein, whose fall 2003 collection draws heavily on Mod, said he was inspired by the era because “the ’60s was a fun decade, and we need to have a bit of fun.”

As for fashion trends, the traditional “ladies” suit is back with its cropped, fitted jackets worn with pearls. The look is a must for fall; otherwise, as Witherspoon’s character, Elle Woods, warns, it’s easy to feel like white open-toed shoes after Labor Day.

Don’t invest too heavily into trends from Hollywood. Fashions these days come and go faster than Jennifer Lopez can switch husbands.

By next summer, everybody may be back in survivalist gear.