Lacking chemistry between its co-stars, The Wedding Date falters as a romantic comedy. Fortunately, Dermot Mulroney, portraying a very expensive male escort, provides enough eye-candy and mystery to save this movie from being a total disaster. He’s suave, charismatic -- and, as Debra Messing’s character tells him, “worth every penny” of his $6,000 fee for posing as her new boyfriend at her sister’s wedding.

Kat Ellis (Messing) is willing to spend that much money on Nick Mercer (Mulroney) because she wants to make her ex (Jeremy Sheffield), the guy who dumped her, jealous. It’s just icing on the cake when women of all ages in the wedding party also show how much they envy her. They drool over Nick in practically every scene. Naturally, before you can say “Surprise!” Kat and Nick fall hard for each other. Too bad their romantic feelings seemed forced and unreal to me. Not at all like the convincing sparks between such couples as Meg Ryan and Hugh Jackman in Kate & Leopold or Sandra Bullock and Hugh Grant in Two Weeks Notice or Drew Barrymore and Adam Sandler in The Wedding Singer.      

Without the necessary on-screen chemistry between leading man and leading lady, a romantic comedy must rely on humor to carry the day. Unfortunately, The Wedding Date also falls short on laughs. Messing, so amusing on TV’s Will and Grace, fails to display her impeccable comic timing here, much to my disappointment. Granted, she doesn’t have much of a script to work with, but I think she needed to try harder, especially in scenes where situations cried out for more exaggerated physical comedy to enliven the story. Some people compare Messing to the late great Lucille Ball, but I saw no such resemblance in this performance.       

Weddings traditionally abound with material for hilarious dramatization on screen. Four Weddings and a Funeral, My Big Fat Greek Wedding, and My Best Friend’s Wedding (also with Mulroney) come to mind. But, as directed by Clare Kilner (How To Deal), The Wedding Date substitutes a series of unfunny scenes -- such as those showing bridesmaids on a drunken spree and silly minunderstandings about who slept with whom -- for that fine comic tradition.

Mulroney, who cracked me up in his almost unrecognizable role as Jack Nicholson’s future son-in-law in About Schmidt, seems placed in a straightjacket by the confines of Dana Fox’s humorless screenplay. Still, his character emerges as the most intriguing, and I wanted to know more about him. Why did Nick Mercer become a paid male escort? What kind of family did he come from? How would he behave in a normal situation? Hmm. Maybe all this has been saved for a sequel.

(Released by Universal Pictures and Gold Circle Films; rated “PG-13” for sexual content including dialogue.)