Is Hollywood finally rethinking its damaging and dangerous belief that the bonier the actress the better? Seems Megan Fox and Eva Longoria have been told to bulk up their twiggy figures for the sake of their respective roles.

"I should have toned up for [the] 'Transformers' [sequel], but I'm really lazy," Megan told reporters at a Television Critics Association shindig on Monday (via FoxNews.com). "I had to put on weight."

The sexiest list-topping Angelina Jolie-alike, 22, apparently whittled her already fat-free frame even further down while working on the zombie movie "Jennifer's Body" and "got really scrawny."

She reveals she was ordered to go up a size for the robot-stuffed flick because director Michael Bay "doesn't like skinny girls," which will likely come as news to Kate Beckinsale, who has previously said she was sent to the gym for four hours a day while working on the schlockmeister's "Pearl Harbor."

Fox says she had to pack on 10 pounds in three weeks, a job she took seriously.

"I have a serious sugar tooth, so now I eat red velvet cake before I go to bed every night," she explains, seemingly unaware that she just alienated the few female members of her fan base, "and if you eat meals later, you'll put on weight faster, so I had dinner at 10 p.m."

While Megan, who attended the fete with her relationship-defending fiancé Brian Austin Green, was happy to dish about her diet, she was less forthcoming about the "Transformers" plot.

"I can't," she demurred. "I'll get fired, and then they'll replace me with Eva Longoria!"

Coincidentally enough, the pocketsize "Desperate Housewives" star is in prime physical shape to take over the role.

People says Longoria has been trying to fill out in order to channel her alter ego, Gabrielle, who, in the show's timeline-leaping fifth season, has transformed from a hard-bodied vamp into a frumpy, overburdened mommy.

"She's making herself look like that as her character has let herself go. Gabrielle has gained weight and cut her hair," her rep explains to the mag. "She's a worn-out mother with two kids."

Just don't expect the newly be-bobbed Eva to go all De Niro in "Raging Bull."

Recent bikini photos show she has retained her sylphlike silhouette (though her barely perceptible weight gain did spark yet another round of pregnancy chatter, which she's once again shot down), and it seems she still needs some ersatz flab to pull off her downtrodden domestic goddess look.

"She's also wearing butt pads and a stomach pad to play the part," says her mouthpiece.

Is Kim giving us a last look at her shapely derriere before it undergoes a Reggie-mandated deflation?

In other butt-padding news (now there's a segue we don't get to use nearly enough), is Kim Kardashian being prodded to deflate her famously bulbous behind?

The New York Post claims her NFL beau, Reggie Bush, has been encouraging her to hit the gym in order to tone up her tuchis and other resplendently curvy parts.

"He's been pushing her to work out hard," a snitch alleges to the paper, which says the reality-starring brunette was overheard at a party this week telling a pal that Bush recently had her feel the burn by hoofing it up the dunes at California's Manhattan Beach.