Patrick Dempsey is out of his element in 'Made of Honor'

If "Grey's Anatomy" heartthrob Patrick Dempsey is to ever fulfill his long-standing ambition of becoming an A-list Hollywood movie star, he's going to have to make much better choices of material than the annoying romantic comedy, "Made of Honor."

The film is harmless enough -- and instantly forgettable -- but it represents a major step down in quality from last year's "Enchantment," a critical and box-office hit that seemed to promise a bright big-screen future for Dempsey.

In this weak follow-up, he plays Tom, a wealthy Manhattan playboy who beds a different supermodel every night of the week but is psychologically dependent on Hannah (Michelle Monaghan), his equally beautiful and sexy -- but platonic -- best friend.

After years of this friendship, Tom decides he loves Hannah. But no sooner does this hit him than she returns from a trip to Scotland engaged to a billionaire Scottish duke (Kevin McKidd), a guy one step below Prince William on the U.K. bachelor eligibility list.

Given their friendship, Hannah wants Tom to be her maid of honor -- a job he accepts so he can stay close to the betrothed couple and find some way in the days and weeks leading up to the big Highland wedding to make Hannah realize she actually loves him.

It's a one-joke premise if ever there was one, and director Paul Weiland ("Leonard Part 6") fails to rise above it. His string of pratfalls and visual gags -- far too many of which kid Dempsey's masculinity -- are groaningly predictable and sitcom stupid.

As a star vehicle the movie is a modest disaster. The script, so feeble it doesn't even let us know what the character does for a living, is poorly tailored to Dempsey's strengths, and he seems so uncomfortable in the role that he's often painful to watch.

Dempsey also needs some fashion advice. As always, he sports his trademark five o'clock shadow in every scene (which in itself is excessive). But with Dempsey at age 42, it's beginning to make his face look more sinister than sexy, less Dr. McDreamy, more Richard Nixon.