The romantic comedy 27 Dresses, which is set in New York City but was filmed largely in Rhode Island early last summer, is a frothy delight that has many charms, even though Aline Brosh McKenna, who wrote the hilarious 2005 screen version of The Devil Wears Prada, offers only scant surprises in her script.

Not the least of those charms is Katherine Heigl as Jane Nichols, a young woman who has become so enamored of weddings that she sometimes travels from one to another in the same night to serve as a bridesmaid at both. Always a bridesmaid but never a bride — but not for lack of trying — it’s no wonder there are 27 bridesmaid dresses stuffed into Jane’s closet.

Jane has carried a torch for her handsome boss, George (Ed Burns), an outdoors enthusiast who heads an eco-conscious sportswear and sporting equipment company called Urban Everest, ever since she laid eyes on him. Unfortunately for Jane, George finds her bright, efficient and as necessary (and interesting) as a coat rack.

Even more unfortunately for Jane, when George first lays eyes on her blonde and vivacious sister, Tess (Malin Akerman, who was the annoyingly awful bride in the Farrelly Brothers’ remake of The Heartbreak Kid), it’s love at first sight for both. Director Anne Fletcher, who keeps this light comedy afloat thanks to Jane’s series of romantic misadventures, stages their first meeting at a festive dance party (filmed at Club Hell in Providence), wonderfully. You can feel the electricity between George and Tess as they make eye contact and slowly approach each other across a crowded room, even as Jane approaches from another direction and quickly begins realizing the chemistry that’s percolating between her sister and her secret love.

Fletcher, a choreographer who previously directed last summer’s surprise hit Step Up, pulls the rabbit out of the hat again with this, her second film, which has tested so well with preview audiences that 20th Century Fox moved its release date from Jan. 11 to today to take advantage of the three-day holiday weekend. Although the dialogue may not be as crisp and pointed as McKenna’s The Devil Wears Prada, the overall tone of the film is breezy.

Things get stickier for Jane when she catches the attention of Kevin Doyle (James Marsden, the fairy tale prince of Enchanted), the cynical writer for the Commitments bridal page in the Sunday edition of a New York newspaper. She first catches his eye as she travels between stints as a bridesmaid at a ritzy wedding in a Manhattan hotel and a Hindu-Jewish wedding in Brooklyn, changing from classy gown to classy sari and back again in a taxicab while going back and forth between wedding gigs. Kevin sniffs a big feature story in the making and hopes it will be his ticket off the “wedding beat.”

What follows are a series of up-and-down romantic quandaries for the always selfless Jane, not to mention Kevin, who finds himself falling for this strange wedding junkie. There’s also the sticky situation Tess finds herself in, having invented a whole vegetarian-outdoorsy-dog loving personality for herself in order to fit in with what she thinks the ever-clueless George wants in a woman. At first Jane tries to minimize the Tess-George relationship, until she inadvertently walks in on his marriage proposal and all the beans are spilled.

In true do-gooder fashion, Jane sets out to help Tess and her wedding plans, even though it means the collapse of all Jane’s own fantasies. Yet soon a sisterly rivalry develops between Jane and Tess, who is all shiny and bubbly and eager as opposed to Jane’s nose-to-the-grindstone sensibility.

There’s also tension between Jane and Kevin, especially once she discovers he writes the Commitments column, her favorite part of the newspaper, under the byline of Malcolm Doyle. But, as in all good romantic comedies, he begins to get under her skin and she begins to let down her guard. In one of the film’s brightest moments, Jane tries on all 27 of her bridesmaid dresses for Kevin and his camera, including a hoop-skirted Scarlett O’Hara number and a Japanese kimono.

You may have figured out not long into the movie how all this will pan out, but McKenna has a few roadblocks and detours to divert us on the way to the inevitable. There are a few moments near the end of 27 Dresses when it seems the story may be headed on a different track. That’s all part of the merriment in what is the season’s first perfect date-night movie. It should play right through Valentine’s Day.

****27 Dresses

Starring: Katherine Heigl, James Marsden, Malin Akerman, Ed Burns.

Rated: PG-13, contains sexual situations, adult themes.

mjanuson@projo.com