Poor patrick Dempsey simply isn't leading-man material.

If you're going to do a gender reversal spin on My Best Friend's Wedding, one of Julia Roberts' best and most enduring chickflicks, it's probably a good idea to find a male star as all-quadrants appealing as Roberts was back in the day when she ruled the box-office roost as America's Sweetheart. Made of Honor flunks that test big time.

With apologies to all you McDreamy/Grey's Anatomy fans out there, washed-up '80s teen idol Patrick Dempsey simply doesn't cut it as a Roberts manqué. Besides the fact that he looks every day of his 42 years and comes across as more smarmy than seductive, Dempsey simply lacks the requisite charm and romantic comedy panache to close the deal. There's a reason Dempsey's career went into the toilet after his Tiger Beat phase ended: He's simply not movie star or even leading man material. Since Dempsey did the best work of his career playing Sela Ward's autistic brother on TV's Once and Again, he might have a future as a character actor. (A Rainman remake would be a natural.) But asking him to carry a film is simply beyond his limited capabilities.

In Made, Dempsey plays roguish man-about-town Tom Bailey who, like Roberts before him, doesn't realize he truly loves BFF Hannah (the likable Michelle Monaghan from Gone Baby Gone, filling in for Dermot Mulroney) until she's ready to walk down the aisle with another dude (Daniel Craig wannabe Kevin McKidd, playing the Cameron Diaz role). For Made of Honor to work, we need to root for Tom and Hannah to 'fess up to their mutual attraction and exchange vows (or at least finally get it on) before the closing credits. That never happens here. In fact, sport fucker Tom - he warns his latest in a string of one-night stands that he doesn't do "back to backs" - is such an unrepentant cad that Hannah comes across as hopelessly dense for putting up with his misogynistic boorishness. Sure, he might be fun to shop and eat dim sum with, but you feel like taking the poor deluded spinster-to-be aside and proffering some much-needed sisterly audience about wasting her valuable child-rearing years on a Peter Pan like Tom.

It's not until Hannah leaves for a six-week acquisition trip in Scotland (she does something vaguely artsy with her Cornell degree) that Tom decides he simply can't live without her. Or maybe he just doesn't like eating Chinese food alone; it's kind of hard to tell from Dempsey's constipated facial expressions. Tom's big plan to finally break the news and confess his undying love backfires after Hannah trots out fiancé Colin (McKidd), the strapping Scottish bloke she met overseas. When Hannah impulsively asks Tom to be her maid of honor, he agrees while secretly vowing to do whatever it takes to steal the bride.

Unlike My Best Friend's Wedding, where Julia's character matured during the course of the movie and realized she was being a selfish rhymes-with-witch for wanting to keep her platonic pal all to herself, Tom never comes to that grown-up realization. And while the screenplay - by Adam Sztykiel, Deborah Kaplan and Harry Elfont - works overtime to portray Colin as a mensch, the movie can't resist showing a few kinks in his armor so that we don't care if Hannah stands him up at the altar in favor of Tom.

Another off-putting feature to Made of Honor is the preponderance of smutty humor which feels tonally inappropriate for a romantic comedy that, with a few minor alterations, could have starred Doris Day and Rock Hudson 40-plus years ago. The lewd jokes about dildos, blow jobs and Ben-Wa balls might work for Judd Apatow since Apatow's rom-com template is a hipper, raunchier, entirely 21st century beast. Made, on the other hand, keeps both feet in the Eisenhower era while tentatively dipping its toes in the gutter for a faux street cred. It's as unworkable - and unsavory - a concept as it sounds.

MADE OF HONOR: Opens Friday areawide