Meanwhile, she told E!: "It's a very 'Happy birthday, Mr. President' dress."
Naomi Watts was expected to wear a gunmetal beaded gown with a geometric cutout on the bodice, also by Armani. She and Chastain were both considered fashion "gets" for the Academy Awards in Los Angeles.
Quvenzhane, with a silver headband in her hair and carrying her puppy purse, wore an Armani Junior navy-blue dress with black, navy and silver jewels scattered on the skirt and a big bow on the back. She apparently has another Armani dress, a pink one, ready for the afterparty. "I liked it because it was sparkly and puffy."
Jennifer Lawrence was in a white strapless gown by Dior Haute Couture with sophisticated pulled-back hair, diamond-ball earrings and a delicate long necklace that hung down in the back.
Amy Adams wore a dove-gray Oscar de la Renta gown with a sweetheart neckline and tiers of frayed chiffon and tulle on the ballskirt, and Zoe Saldana wore a strapless gray gown with floral appliques. Reese Witherspoon's modern gown by Louis Vuitton was mostly electric blue with a strip of black at the bustline.
Kerry Washington wore a Miu Miu gown with a chunky beaded bodice and orange-red skirt with a delicate bow at the waist.
Other expected designer moments to unfold at the Dolby Theatre include Barbra Streisand in a black, bias-cut, asymmetrical Donna Karan gown that the designer dubbed "City Lights." Renee Zellweger was expected to wear a Carolina Herrera gown.
Headed to the Oscars herself, Nadja Swarovski, the head of corporate communications for the crystal company Swarovski that makes the beadwork for the majority of the red-carpet gowns, expected the collective fashion picture to be fairly minimalist looks in monochromatic colors.
Still, she said, there'll be sparkle. "It's more of a dot on the 'I' or cross on the 'T,' more than a whole of sparkle, but it makes a great palette for jewelry."