The Academy Awards nominees have hit the red carpet, with actresses Jessica Chastain and Amy Adams among the early arrivals.
Jessica, a best-actress contender for Zero Dark Thirty, blew a kiss to cheering fans, who chanted "Jessica!" and looked stunning in her Armani Prive dress.
The actress told E!'s Ryan Seacrest why she had picked her gown: "I chose it because I'm such a fan of movies, I love cinema so much. It reminds me of old Hollywood glamour.
Jessica, who took her grandma as her Oscars "date" said of the big night: "I'm freaking out. Last year I was a bit stunned by it, like the fog of it. And this year I can see clearly now and I'm like 'I'm nominated for an Oscar. Oh my God!'."
Amy Adams, nominated for her role in The Master, talked about how she will be playing Lois Lane in her next role in Man Of Steel.
Asked if she will be using previous versions of the role as an inspiration, she said: "I think it's always important to pay attention to people who went before you. Take what works for the film that you're doing but then add a modern touch."
Reese Witherspoon said her daughter helped her pick her dress for Oscars night. "She makes sure she likes everything. She helps me pick the jewellery, the make-up, everything."
Reese also revealed that she had written a letter to Naomi Watts in praise of her Oscar-nominated performance in The Impossible. She said: "Not since I'd seen Meryl Streep in Sophie's Choice had I seen a performance that moved me so much."
Jennifer Lawrence, wearing an elegant Dior Haute Couture gown, admitted she hadn't eaten before the Oscars ceremony. She said: "Today was stressful and I had no time to eat. I am starving.
"Everybody in my family got ready at my house. I felt like Steve Martin in Father Of The Bride."