From Here to Maternity: When we were growing up, our mother nagged us to be ladylike and always wear a slip. Looks like Britney Spears got the same advice. Too bad she didn’t bother with the whole skirt part of the equation. The pregnant pop tartlet turns up for the premiere of “Charlie and the Chocolate Factory” in a rumpled, lace-trimmed lingerie-like number that’s unfortunately the exact hue of the brown carpet she’s trodding on. Brit, ever the PR pro, also styles a baby blue tank top with a dual-purpose logo: Not only does she plug the flick, to which she has no connection, but she helpfully reminds us of the bun (or possibly buns) in her oven. Just in case we’d forgotten. Of course, when it comes to the Britster and maternity wear, it’s all a matter of degrees. Even with her matching blue wedges, this ensemble is a major improvement over some of her recent belly-baring blunders, although it still fails to flatter her rapidly changing shape. Spears is also less than successful in her attempts to accessorize. While her multiple bracelets and necklaces work fine, that unshaven decoration on her left arm needs improvement. Kevin Federline, looking like he smells faintly of cigarette smoke and apathy, makes the scene in rolled-up jeans, an untucked shirt and a thrift store-looking jacket covered in what we’re guessing (based on our own queasiness with all things Federline) are Pepto-Bismol stains.