Now that Joan Rivers has done to death the red carpet question: 'Who are you wearing?', the TV anchors at awards shows and movie premieres must think up something more original to ask. At the Emmys earlier this month, the big question was: How'd you lose the weight? Of course, that had everything to do with the fact that a number of stars were new mums who had miraculously rebounded to their pre-birth figures. This is a town that celebrates a woman's body considerably more than her talent. Think Jessica Biel, Jessica Alba, Halle Berry - women whose figures made them famous long before any on-screen accomplishments. But a new mum - that was sacred. Actresses who'd just given birth were allowed to take some time - but not too long - to get back into shape. It was a given. They were nursing and nurturing a newborn, and should be more concerned about that than scheduling time with a personal trainer. Then, as often happens in Hollywood, one actress comes along and spoils it. In this case it was Denise Richards, ex-wife of Charlie Sheen, who posed for Playboy when her baby was just five months old. I recall talk show host Ellen DeGeneres asking Richards at the time if she basically went straight from the labour room to the treadmill. Richards laughed - but sort of agreed. She dieted. She worked out obsessively with a trainer. And five months later, she jetted off to the Bahamas with Sheen in tow and baby girl Sam and frolicked naked on a beach for Playboy, looking as fit as a 17-year-old cheerleader. But that's nothing compared to the accomplishment of German model and Project Runway chieftain Heidi Klum. When she had her second child a couple of years ago, she hit the Victoria's Secret runway eight weeks after giving birth. There were no stretch marks, no cellulite, no remnant of a paunch where a baby once grew. She now has three children under the age of four, but you'd never know it by looking at her. After that accomplishment, heaven help any new celebrity mother who keeps pregnancy weight on longer than about three minutes post-partum. Katie Holmes made it her Mission: Number One to shed the pounds after the birth of her and Tom Cruise's daughter Suri, because she had an Armani wedding dress to get into, for heaven's sake. Jennifer Garner, whose baby with hubby Ben Affleck was born 17 months ago, looked ultra-trim within months; she filmed new flick The Kingdom when daughter Violet was seven months old and that famous Alias tummy was already runway flat, her hips and thighs snapped back into shape. For some actresses, it hasn't been a huge priority. I remember interviewing The Matrix's Carrie-Anne Moss a few years ago, and her saying that she did 'absolutely nothing' for the first year after her son Owen was born because she wanted to enjoy motherhood without worrying about weight. (That said, I talked to her a few months after that, and she was back to her willowy self ... but at least she had that one-year window). But now every woman in Hollywood who has a baby is held to these impossibly high standards: when Britney Spears appeared at MTV Video Music Awards in Las Vegas recently, she was roundly chastised for her pitiable lip-synching, faulty dance moves and generally 'phone it in' performance. She was also called 'out of shape'. I checked out the clip on YouTube and thought she looked fit for a mother of two toddlers - no jiggling tummy or boob sag. What else do you want? Alas, everyone will now aspire to the levels of the likes of Marcia Cross. The Desperate Housewives star gave birth to twin girls six months ago. But when she stepped onto the red carpet at the Emmys, there was nary an extra pound of weight on her. Her advice: to make 'one decision at a time' - which sounds as if she's not exactly willing to part with her secrets. Far more forthcoming was Jaime Pressly, who won that night for her part in My Name is Earl, and who looked spiffy and slender with a five-month-old baby at home. How'd she do it? She hit the gym 10 days after giving birth, exercising two hours a day, five days a week while following the Cabbage Soup diet, which basically involves reducing the body's intake to near-starvation levels. Here's the kicker though: Pressly's character on the show is pregnant, and the actress now has to spend several hours a day heaving around the set in a fat suit. It probably would have been easier for her to lay off the cabbage soup. That's justice for you, Hollywood style.