Ashton Kutcher (Dude, Where's My Car?) and Brittany Murphy (8 Mile) waste their star power in this lackluster romantic comedy from Shawn Levy. The ill-conceived plot du jour tosses two lovers from opposite sides of the tracks into an impetuous marriage. It's not until their honeymoon in Europe that they discover those little dark secrets about each other that could spoil their wedded bliss. As DJ wanna-be Tom, Kutcher recycles his wide-eyed goofball persona pleasingly -- though at times he seems to be paying homage to Tom Green. It's Murphy who plays against type as a bubbly, blonde rich girl from Beverly Hills. Her Sarah is reminiscent of Reese Witherspoon's lovable ditz from Legally Blonde -- and Murphy is adept at the cute-perky shtick, too. Beyond the pair's improbable meeting, Just Married is devoid of romance. It opens with their tumultuous near break-up and then bides its time retracing the trite ticks that brought them to that point. Aside from a few funny bits involving the Mile High Club and a French bulldog, this is a turgid affair that the two budding stars (a couple in real life) should have said no to. (95 minutes) At the Entertainment, Flagship, Holiday, Narragansett, Providence Place Mall 16, Showcase, and Tri-Boro cinemas.