Stars who make weight gain look good Michelle Williams stars in "My Week with Marilyn" Renee Zellweger, Bridget Jones Amy Adams,...

Stars who make weight gain look good

Michelle Williams stars in "My Week with Marilyn"

Renee Zellweger, Bridget Jones

Amy Adams, The Fighter

Julia Roberts, Eat Pray Love

Hilary Swank, Million Dollar Baby

These five celebrities packed on the pounds for a movie role with sexy results.

Michelle Williams is earning raves (and tons of Oscar buzz) for her performance as Marilyn Monroe in the upcoming film My Week with Marilyn. And talk about dedication to your craft: Since the tiny actress doesn't quite have Marilyn's legendary curves naturally, she packed on a few pounds for the role.

"I wasn't watching what I ate, let's put it that way," Williams, 31, told People magazine at the movie's New York premiere (it hits theaters this Wednesday).

But the transformation didn't stop there. Williams watched Monroe's movies non-stop, studied her voice and perfected her famous wiggle, which she practiced by tying a belt around her knees, according to Newsweek. She also had to bleach her hair every few days, so it wouldn't show under her blonde wig, and spent hours in makeup each day.

The finished product? Bravo! Williams morphed into Marilyn with uncanny results (based on the sneak peek in the trailer). But she's not the first actress to gain weight for a role -- and look hot doing it.

Here are four more stars who looked even sexier with a little more meat on their bones:

Renee Zellweger, Bridget Jones

The rail-thin actress reportedly gained 28 pounds (by eating pizza and doughnuts) for her Oscar-nominated role as the weight-battling heroine in 2001's Bridget Jones's Diary. She then did it again for the 2004 sequel, Bridget Jones: The Edge of Reason. We don't know about you, but we thought she looked cute in those granny panties!

Amy Adams, The Fighter

For her Oscar-nominated role as a boxer's tough-but-sweet girlfriend in The Fighter, Adams didn't so much try to gain weight as put off losing the post-baby pounds -- at the director's request.

"He said, 'I want you to look like a girl who drinks beer,'" Adams told Parade magazine. And Adams did end up looking like a very sexy -- and very real -- girl next door.

Julia Roberts, Eat Pray Love

Guess they had to do something about that "Eat" section. Roberts gained 7-10 pounds for Eat Pray Love (to look like a woman eating her way through Italy), but she looked lovely as always. Bonus: Healthy Italian Recipes

Hilary Swank, Million Dollar Baby

Swank didn't quite put "meat" on her bones -- rather, she gained 19 pounds of muscle (and won the Oscar for her convincing portrayal of a female boxer). To do it, she reportedly ate every 90 minutes and consumed 210 grams of protein daily. Proof that you can look fabulous at any size!