Credit: Jason Merritt/Getty; Steve Granitz/

Sunday's Academy Awards marked the biggest night of the year in Hollywood -- and both newcomers and veterans pulled out all the stops for their evening wear when they arrived at the Hollywood & Highland Center in Hollywood.

But two red carpet rookies in particular stood out: Jessica Chastain and Rooney Mara.

Chastain, who received a nod for Best Supporting Actress for her role in The Help, sparkled in a black and gold Alexander McQueen gown teamed with a whopping $2 million worth of Harry Winston jewels.

Meanwhile Mara, who starred in The Girl with the Dragon Tattoo, surprised everyone when she ditched her usual black attire and stepped out in a white, fashion-forward Givenchy number.

Click here to see what other celebs like Gwyneth Paltrow, Cameron Diaz, Michelle Williams, Jennifer Lopez and more wore at the 2012 Oscars.