With the 85th annual Academy Awards just days away, stars are logging their last marathon sweat sessions with trainers, swigging bottles of organic juices for their cleanses and perfecting their camera-ready poses before making their way down the red carpet Sunday night.

While the race for Best Picture is tight, the real contest of the night is best dressed. Stars like Jennifer Lawrence, Jessica Chastain, Anne Hathaway and Kerry Washington are sized up during awards season for their daring (and not-so daring) choices in the sartorial department, but the Oscars are arguably the night when these stars need to look their best.

Some predict Oscar ballot winners, but for the actresses in the spotlight starring in this year's Academy-award nominated films, the contest on the carpet is one not to be missed.

Cast Your Ballot!

We asked E!'s Fashion Police co-host George Kotsiopolous, InStyle Magazine's Editor-at-Large Hal Rubenstein, and on-air personality and style expert Katrina Szish to weigh in on which looks they thought these stars rocked, what mistakes they hope they never repeat, and which designers' dresses they should sport at this year's Oscars.

Nominated in the Best Actress category for her turn as the no-holds-barred CIA agent who stops at nothing to catch Osama Bin Laden in "Zero Dark Thirty," Jessica Chastain, 35, has hit the awards circuit this year in vibrant blues and reds from the likes of Roland Mouret, Calvin Klein, and Alexander McQueen.

"[Chastain] has a very unique beauty to her," Rubenstein said. 'She should be taking chances."

While her low cut robins egg blue Calvin Klein gown at the 2013 Golden Globes got mixed reviews , Kostiopolous said he was surprised people found it such a polarizing look for the 35 year old.

"Everyone was saying her boobs looked like they were saggy," said Kostiopolous. "What are you saying, you see her cleavage!"

For the Oscars though, Szish said she hopes Chastain strays from dresses with silhouettes on the bottom that are tight and sexy, which she tends to favor, but should stick to wearing bold hues.

"I think she does so well in color," said Szish. "I love her in yellow, especially with her hair, it's gorgeous. I could even see her doing a bright pink."

As far as designers go, Szish said she could see Chastain opting for Vera Wang or revisiting Alexander McQueen, whose red stunner she donned at this year's SAG Awards. Kostiopolous said he hopes Chastain goes for something custom-made.

Rubenstein agreed. "When somebody has a set of features or a presence that is so unique or so individual, she should make it her business to stand away from the pack and try things that are one of a kind," he said.

"Anne loves fashion, Anne loves clothes, and designers love Anne. I mean, especially this time, she is the girl to get. She has the clear odds in her favor to win," Rubenstein said of Hathaway, who has been considered a lock for the Best Supporting Actress category for her portrayal of Fantine in "Les Miserables."

But at the Oscars, Kostiopolous said most actresses play it safe, sartorially speaking. While Hathaway, 30, showed her edgier side at premieres, she saved prettier looks - like the white Chanel gown she wore to this year's Golden Globes - for awards night, he said.

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"What you wear on Oscars' night is kind of like a wedding photo," Kotsiopoulos said. "You want your wedding portrait to look classic and beautiful, you don't want to cringe at it in 30 or 40 years. I think that's why we see more conservative fashions on the red carpet."

Though pretty she might have looked, Szish said she thought Hathaway got it all wrong in the black sheer Giambattista Valli she chose for the 2013 SAG Awards.

"The sheer top with the plain lines - the sleeveless shift silhouette on the top was so not flattering for her, " she said. "She has such a sleek silhouette. It was just too fussy for her."

While Szish and Rubenstein both agree Hathaway should opt for designs from Valentino or Chanel, Rubenstein said he hopes the actress surprises in Lanvin.

"I don't really think actresses should really be worried about what people sitting in their chairs on Monday morning are saying," he said.

"There are a lot of women who look the same in Hollywood," said Rubenstein. "Anne certainly doesn't - that kind of singularity deserves one of-a-kind pieces and she has earned the right to sort of play the field."

As the newest face of Miss Dior, Lawrence, 23, has favored the brand at the SAG Awards and the Golden Globes. And our panel expects that the "Silver Linings Playbook" actress, who is a serious contender in the Best Actress category, will also be stepping out in Dior at the Academy Awards.

In her strapless red Dior Haute Couture gown, "she looked like a super sexy old Hollywood siren at the Globes," said Szish. "But I didn't like the dress [at the SAG Awards]. I didn't like the color, there was nothing special about it at all."

But Rubenstein disagrees.

"She's young and she looks beautiful," he said. "She's a great role model for young women to show off their bodies instead of hiding them."

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"If you notice, the clothes that we've liked with the red Dior [at the Golden Globes] or the red Calvin Klein at the Academy Awards last year, she's not embedded in embellishment, and I think that plays to her strengths," said Rubenstein.

But even Kostiopolous said he's surprised he hasn't seen more distinctive gowns on Lawrence.

"I would expect the girl who's the face of Dior to have custom-made clothes," he said.

Szish said she wants to see Lawrence wear something like the embellished strapless Dior Haute couture gown she rocked at the BAFTAs on Feb. 10.

"She was much more sultry, modern and edgy," she said. "I thought she looked spectacular in that cream colored dress."

"The simpler outfit she's in, the easier she moves," said Rubenstein. "But you do always get the sense that she's ready to kick off her shoes."

"I think someone like Kerry is starting to get off on fashion for the first time," said Rubenstein. "I see more courage and boldness in her choices. Consequently, she's more interesting to watch."

Rubenstein said Washington, who starred in Quentin Tarantino's "Django Unchained," nominated for Best Picture, seems to have grown into her looks and become more comfortable with her body, which is reflected in her red carpet choices.

"If you look at the Miu Miu dress she wore to the Globes with the straight flat iron hair, I thought she looked really cool and really striking," he said.

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"She's obviously the most fashion forward of the bunch," Szish said. "She'll take risks that a lot of other actresses wouldn't take on the red carpet and she's been able to pull it off really well."

Szish said she was a fan of the white Rodarte gown with blinged out bodice and lace detailing the "Scandal" actress wore at the 2013 SAG Awards, but couldn't get over the pink and green brocade Oscar de la Renta the actress wore at the 44 th annual NAACP Image Awards.

"I know what she was trying to do with the color blocking at the lace, but on her proportions, it just didn't work."

But Kostiopolous stuck up for Washington's pick.

"I don't think that was a huge risk. I thought it was beautiful for Kerry," he said. "From the back it was absolutely stunning, but I think the fit was a tiny bit off."

"Oftentimes the most fashionable girls are on the best dressed lists and the worst dressed lists because the fashion crowd will love it, but the US Weekly's and the tabloid crowds…It will be on the worst dressed list because it's not as understood," Kostiopolous said. "So the trick is to get on both of those lists. You have to push the limits just enough to be fashionable."

For Oscars' night, Szish said she'd like to see Washington retain her style edge in designs by Prabal Gurung or Jason Wu, or maybe even opting for another classic American designer, like Carolina Herrera.

Make sure to tune in to Backstage Pass on Oscar Sunday to see your favorite celebrities walk the red carpet and follow the winners backstage. Click here to learn how!