Our PicksBest & Worst Dressed of the WeekThe Fashion Beast Team01.10.14Our PicksBest & Worst Dressed of the WeekJessica Chastain stuns in yellow de la Renta, the cast of 'Girls' gets dressed up, and Margot Robbie wears a high-fashion doily. Plus, more best and worst dressed of the week.The Fashion Beast Team01.10.14 10:45 AM ETGetty (2); AP (2) Jessica Chastain stuns in yellow de la Renta, the cast of Girls gets dressed up, and Margot Robbie wears a high-fashion doily. Plus, more best and worst dressed of the week. Ian Gavan/GettyBest Dressed in Pastels: Lea SeydouxFrench actress Lea Seydoux, who's the face of Miu Miu's Resort 2014 campaign, kept things feminine for the EE Rising Star Award photocall on January 6 in a high-neck, long-sleeved, skater-style dress printed with flowers from the designer. She accessorized with a light pink, embellished wool coat by Prada, and mint-green pumps with orange detailing, also by Miu Miu. Evan Agostini/Invision, via APBest Dressed, Sunny Days: Jessica ChastainJessica Chastain attended the National Board of Review Awards Gala on January 7 in a yellow, knee-length silk dress and blue pointed-toe pumps with silver and yellow detailing, both from Oscar de la Renta's Spring/Summer 2014 collection. Andrew H. Walker/GettyBest Dressed Group of Girls: Jemima Kirke, Lena Dunham, Allison Williams, and Zosia MametFor the season three premiere of their hit show, Girls, on January 6, stars Lena Dunham, Jemima Kirke, Allison Williams, and Zosia Mamet were dressed to the nines. Kirke kept to her bohemian aesthetic, sporting a silk, lingerie-style vintage Geminola dress. Dunham stood out, looking fabulous in a silver, sequined dress from Rochas's Spring/Summer 2014 collection with Jimmy Choo heels. Williams wore a girly, short light-blue frock with floral appliqués by Christian Dior, and Zosia Mamet opted for a classic Saint Laurent little black dress. Jordan Strauss/Invision, via APBest Dressed, White Lace: Naomie HarrisNaomie Harris stunned at the Palm Springs International Film Festival Awards Gala on January 4 in a white, lace gown with a black waistband from Naeem Khan's Spring/Summer 2014 collection and Jimmy Choo shoes. Cindy Ord/GettyBest Dressed, Tin Woman: Cate BlanchettFor the 2013 New York Film Critics Circle Awards on January 6, actress Cate Blanchett stunned in a silver Antonio Berardi dress, with a peeking red lining, and a coordinating bolero. She accessorized the look with Van Cleef & Arpels jewelry and black Christian Louboutin heels. Frazer Harrison/GettyWorst Dressed in a Doily: Margot RobbieA promising style star, up-and-coming actress Margot Robbie took too much of a fashion risk at the Australians In Film screening of The Wolf Of Wall Street on January 7. Robbie's Delpozo dress looked like an awkward doily pinned upon suspenders, stealing attention from her natural beauty. Rotello/RexWorst Dressed, My Little Fashion Mistake: Rita OraLooking fresh out of a Lisa Frank trapper-keeper, Rita Ora partied at the Chinawhite nightclub in London on January 4 wearing a My Little Pony x Alice Vandy collaborative mini-dress and thigh-high Ferragamo boots.