The gown chosen for the red carpet at the Academy Awards can define a significant moment in any actress’s fashion DNA—whether good or bad.

Here’s a look back at some of the most memorable gowns in Oscar history.

Hepburn clashed with Edith Head after the actress went to Paris and picked out outfits for “Sabrina” from Hubert de Givenchy. She stood out from the crowd in her white Givenchy cocktail frock at the 1954 Oscars. It also marked the beginning of a six film partnership between the actress and the French designer.

For the first Oscar telecast broadcast in color, Christie, nominated for her portrayal of a fashion model in “Darling,” sported this sleeveless gold lame pant suit. She beat “Sound of Music” star Julie Andrews, who wore a searing red kimono dress with a white mink wrap to the ceremony.

She may have lost in the Best Actress category to Gwyneth Paltrow, but in her luscious purple Dior dress by John Galliano, Blanchett was a fashion winner. She collaborated with Galliano on the details of the dress, down to its hummingbirds and elaborate floral embroidery on the plunging back.

The simplistic taffeta pink gown by Ralph Lauren still meets praise and disdain to this very day by the fashion community. However, it accompanied the young Palthrow in claiming the award for Best Actress for her role in “Shakespeare in Love.”

Her vintage Jean Desses gown may have been upstaged by Bjork’s infamous swan tutu, but Zellweger helped kick start a movement among Hollywood actresses to wear vintage on the red carpet.

Roberts was all smiles when she won an Oscar for her work in “Erin Brockovich.” Her dress was vintage Valentino, distinctive with it’s white piping and Y-shaped neckline. Very classy. Her space-age bouffant hair-do was another story, however.

Designed by Marjan Pejoski, the Icelandic singer’s infamous “swan dress” stole the spotlight at the 73d awards.

A barely-there Elie Saab kept Berry out of the ranks of the cliche Oscar gown.

In a sea of cream colored silk with a plunging neckline by Marc Bouwer, Jolie went from a questionably stylish starlet to a glamorous movie star.

O.K., Hil, we get it. You tirelessly sculpted your body to play Maggie Fitzgerald in “Million Dollar Baby.” Swank showed off her toned assets in this high-necked, sapphire-blue Guy Laroche gown. One question still remains: how exactly did she get it to stay in place?

“It” girl Portman looks like a modern goddess in this daring dress by “It” designer Lanvin. The plunging neckline and slightly see-through material push the fashion envelope, yet Portman pulls it off with polish and shine.

Before she was Mrs. Tom Brady, the Brazilian model accompanied her then-boyfriend and Best Actor nominee to the 77th annual Academy Awards in a white strapless Christian Dior gown. Opting for a matronly but elegant empire waist dress that covered and concealed showed a sophisticated side of the typically swimsuit-clad Bundchen.

Once a siren, always a siren. You can count on Hayek to spice up the red carpet in bright hues and curve-hugging numbers. This royal blue Versace gown suited her to a saucy T.

The actress stunned critics in a dramatic feathered train Atelier Versace gown.

A multi-year nominee and 2004 winning actress wore a jaw-dropping silver Armani Prive column gown.

In a champagne and silver Marchesa gown, Bullock represented a modern age of style and grace when she accepted the award for best actress for her role in “The Blind Side.”

Jolie’s black velvet Atelier Versace at 84th annual award show featured a daring leg-baring slit that inspired an entire year of copycat red carpet fashion moments, a flood of web memes, and even a parody Twitter handle.