"27 Dresses" a bad fit for Katherine Heigl

Having nicely established her big-screen credibility with the summer hit "Knocked Up," Katherine Heigl tries a little further "Grey's Anatomy" moonlighting on for size with "27 Dresses."

But while Heigl is terrific, this uninspired romantic comedy is considerably less so.

A tired pastiche of the 27-odd wedding-themed vehicles that preceded it, the film essentially slaps together all the stuff that worked so well the first or second time around, minus any of the original charm or verve.

That it manages to function at all is mainly Heigl's doing, but judging from the half-empty theater reserved for the picture's post-Christmas sneak preview, even her fans might get the sense that they've walked down this aisle many times before.

Heigl's not-so-plain Jane is the owner of those 27 dresses -- a perennial bridesmaid who has kept all of them, no matter how hideous -- squished into the closet of her already-cramped New York apartment with the hope of one day being the main attraction.

She has always been there for her friends and longtime boss (Edward Burns), for whom she has harbored an unrequited crush, but her charitable instincts are about to be put to the supreme test when her bratty, globetrotting kid sister (Malin Akerman) comes to town and proceeds to strike up an instant love connection with said employer.

Meanwhile, Jane also has been fending off the perpetual advances of a cynical writer (James Marsden), who, unbeknown to her, pens those Commitment columns in the New York Journal, which she has been secretly clipping out for years.

Will Jane finally find happiness with the right guy or is she destined for Bridesmaid's Dress No. 28? Does the devil wear Prada?

It so happens that the person responsible for the "27 Dresses" script is none other than "The Devil Wears Prada" screenwriter Aline Brosh McKenna, but in fashion world parlance, this one's a shameless knockoff.