1 of 31
HALLE VS. SIENNA
paired her Isabel Marant blouse with a vest and skinny pants for an L.A. bash, while picked the matching skirt for her metallic-striped top at the British Film Festival.
2 of 31
BLAKE VS. ALEXA
The Gossip Girl lit up an N.Y.C. screening in her peekaboo Chanel dress, while the fashion It girl toned down her mini with flats for the Chanel show in Paris.
3 of 31
REBECCA VS. SALMA
The Town star kept her YSL jumpsuit simple for the Toronto Film Festival, while the added a blazer to her red-and-black one-piece for Paris Fashion Week.
4 of 31
ROSE VS. KELLY
The Aussie actress showed off her legs in her Zac Posen minidress at a premiere in May, while the reality star flaunted her newly svelte figure in her LBD at an October magazine party.
5 of 31
ASHLEY VS. BLAKE
The Twilight hit an award show in May in her cream Antonio Berardi dress, while The Town headed to the film’s Fenway Park premiere this week in the black version of the lacy sheath.
6 of 31
KATE VS. LILY
The went Hollywood glam in her Louis Vuitton cape at the Tribeca Film Festival, while the covered up her bump in the graphic gray-and-black topper during London Fashion Week.
7 of 31
KRISTEN VS. KIMORA
The wore her Hervé Léger as a mini to the Adventureland premiere in March, while the fashion designer paired her coral dress with black leggings for Fashion Week.
8 of 31
RACHEL VS. ISABEL
The Best Dressed pairs her Alexa Chung for Madewell dress with brown accessories for a day out in L.A., while the Transformers actress keeps it simple with her polka dotted dress for a stroll in N.Y.C.
9 of 31
STEPHANIE VS. DENISE
Same night, same dress! Denise Richards picked her bebe dress for the brand’s STYLE360 runway show, while Pratt turned up several hours later for the after party in her leather and tweed dress.
10 of 31
RIHANNA VS. JENNIFER
The strutted out of her N.Y.C. hotel rocking Stella McCartney’s sheer-topped dress, while the showed some skin in the same sheath at the Toronto Film Festival.
11 of 31
JANE VS. OLIVIA
The 30 Rock star wears her floral Stella McCartney frock to a gala in New York City, while The City girl adds a pop-of-purple to the look for The Romantics after party also in N.Y.C.
12 of 31
MAGGIE VS. TARYN
topped her pretty halter dress off with a striped Loft cardigan at an event for the label, while Manning added the affordable find to a fur vest and printed tank during Mercedes-Benz Fashion Week.
13 of 31
LIV VS. CLAUDIA
The kept her printed Mulberry dress simple with minimal accessories at Comic-Con, while the supermodel added a statement necklace and black tights to her bold mini for Fashion’s Night Out in Berlin.
14 of 31
KIM VS. ADRIENNE
adds a metallic belt to one of her own designs for bebe at a ShoeDazzle.com event, while the former Cheetah Girl cinches the same wrap dress with basic black at a party in New York City.
15 of 31
VICTORIA VS. LEIGHTON
The models her own two-tone dress at a Range Rover event, while slips into character as Gossip Girl’s Blair Waldorf in her shimmering beige sheath.
16 of 31
LAUREN VS. COBIE
The revealed her “Milk” ad in her 3.1 Phillip Lim jumpsuit, while the How I Met Your Mother actress picked her navy one-piece for the Entertainment Weekly and Women in Film pre-Emmy party.
17 of 31
JENNIFER VS. CATHERINE
The arrived at a Moscow charity event in her Lanvin dress, while the legendary French actress picked her asymmetrical gown for a walk on the Venice Film Festival red carpet.
18 of 31
LO VS. LOUISE
The former Hills star topped her French Connection dress with a bouffant chignon at a bash for the brand, while the Plain Jane host picked edgy booties to go with her beaded mini at an L.A. style event.
19 of 31
SIENNA VS. VALERIA
The hit the Costume Institute Gala in her Emilio Pucci gown, while the Italian actress attended a Venice Film Festival premiere in her plunging navy gown.
20 of 31
KRISTIN VS. KIM
The paired her Hannah Marshall dress with white heels for an L.A. awards show, while the added a clear belt to her leather-topped dress for a magazine bash in L.A.
21 of 31
HEIDI VS. CHERYL
They may be in camo, but it’s hard to miss these stars! paired her Paige “Super Tanzania” jeans with a tunic for a day in the park, while Cole added a military jacket to her skinny camo jeans for a book signing in London.
22 of 31
JENNIFER VS. HILARY
The new American Idol wore her Roland Mouret sheath to a German photo call in May, while the picked her asymmetrical dress for an N.Y.C. charity event in September.
23 of 31
RIHANNA VS. JADA
The celebrated boyfriend Matt Kemp’s birthday in L.A. in her Emilio Pucci dress, while the actress wore her leopard dress to a party during Milan Fashion Week.
24 of 31
VICTORIA VS. BAR
The first showed off her Roberto Cavalli gown in 2006, while the model pulled her look from the designer’s archive to celebrate his 40th anniversary during Paris Fashion Week.
25 of 31
KRISTIN VS. ANNALYNNE
The braved N.Y.C. traffic in her Old Navy coat, while the 90210 star topped her casual outfit with her red peacoat to run errands in the Big Apple.
26 of 31
MARISA VS. AMY
Tomei picked her strapless Preen dress for the N.Y.C. premiere of Cyrus in June, while Smart chose a version with straps for the ARCADE Boutique and Children’s Institute Autumn Party in L.A.
27 of 31
ANNA VS. CATE
The True Blood star changed into her Alexander McQueen sheath for Emmys after parties, while the paired her black sheath with Roger Vivier accessories for an Australian award show.
28 of 31
KHLOE VS. KIM
Sister smackdown! Khloe wore her bandage dress from the siblings’ line for bebe first to a concert, while wore her second-skin dress for a girls’ night out in L.A.
29 of 31
JENNIFER VS. ALEXIS
The new American Idol visited Today in her red Halston mini, while the actress paired her scarlet sheath with black accessories for the line’s fashion show during N.Y.C. Fashion Week.
30 of 31
SOFIA VS. GAIL
The Modern Family bombshell covers her curves in a Lela Rose dress for the Emmy nominations, while the Top Chef Just Desserts host belts her cobalt number for a magazine party in N.Y.C.
31 of 31
JENNA VS. MEL B
The Glee costar picked her WTB dress for a FOX TCA party in August, while the former Spice Girl selected her leather peplum dress for the Creative Emmy Awards later that month.