You could write this one in your sleep. A married couple sends two of their friends, bubbly caterer Holly (Katherine Heigl) and playboy TV technician Messer (Josh Duhamel) on a date that goes badly. That should be the end of that, yet the fallout of a tragedy requires that the two live under their friends’ roof and raise their baby. The debate is low. Will they? Won’t they? Can he change a nappy? This is yet another spin on the mismatched-couple comedy, although luckily there’s enough of a spark between Heigl and Duhamel (in contrast, say, to Gerard Butler and Jennifer Aniston in the disastrous ‘The Bounty Hunter’) to distract from the obvious plotting and faceless direction. Duhamel’s one-note, ‘immature jock’ shtick is hard to warm to, but Heigl offers an easy comic naturalism. At best, it feels like there’s a more serious drama simmering under the surface. At worst, we have to endure Heigl and Duhamel’s excruciating ‘stoned’ act.