Lifestyle Style Stars' Day-to-Night Style Reese Witherspoon, Kristin Wiig, Vanessa Hudgens and more rock changing styles as the sun sets By Alex Apatoff Alex Apatoff Instagram Twitter Alex Apatoff is the Executive Editor of PEOPLE Digital. She has been with the brand for more than a decade, holding various roles on the Style and Beauty team before becoming the site's Lifestyle Director to coordinate the work across the commerce, evergreen, features and marketing teams. Prior to her role at PEOPLE, Alex worked at Us Weekly (where, among other things, she oversaw the Fashion Police pages) and graduated from Northwestern University with a Bachelors in Journalism. People Editorial Guidelines Published on June 6, 2011 10:00 AM Share Tweet Pin Email Trending Videos 01 of 11 REESE WITHERSPOON Pacific Coast News; Don Arnold/WireImage During her worldwide Water for Elephants press tour, the took advantage of her exotic locales. She played tourist in Sydney on May 6 in a black turtleneck, crossbody bag and booties, then went all-out glam in a strapless Zac Posen dress and major ringlets for her nighttime premiere. 02 of 11 KRISTEN WIIG GSI Media; Marcel Thomas/FilmMagic Bridesmaids’s breakout star headed into The Late Show With David Letterman on May 9 in a flowing top, cuffed jeans and pink clogs. But she exited the taping in an elegant high-necked satin frock, leopard pumps and a sleek updo. 03 of 11 HILARY DUFF KMM/X17; Norman Scott/Startraks hit the gym in L.A. May 11 in neon sneakers and a high pony. She showed off the results of her workout at a party that night, baring her toned arms and legs in a Diane Von Furstenberg top, belted skirt and nude pumps. 04 of 11 VANESSA HUDGENS Eliot Press/Bauer-Griffin; Todd Oren/Getty The took a Cannes-do approach to dressing while in France for the film festival, wearing beachy Levi’s jean shorts and a tunic to arrive at her hotel on May 15. She then hit a Vitaminwater bash in high style in a one-shoulder Fendi gown and champagne clutch. 05 of 11 KIRSTEN DUNST Mike Marsland/WireImage; Dominique Charriau/WireImage Also at Cannes, the Melancholia attended a May 18 photocall for the film in a sweetly summery Chloé dress and Jimmy Choo sandals. She then amped up the vamp factor in her curve-hugging Rodarte gown and Bulgari bracelet at its premiere that evening. 06 of 11 GWEN STEFANI INF; Joseph Kerlakian/Startraks Though the is perpetually glam, wearing red lips and cat-eye sunglasses with her belly-baring ensemble to hit the beach in Cannes on May 20, she dialed up the look for evening by sporting a major smoky eye and sleek Armani Privé gown to the premiere of This Must Be The Place. 07 of 11 JENNIFER LOPEZ Ramey; Kevin Mazur/WireImage PEOPLE’s most beautiful doesn’t take time off from looking great! She’s as equally polished in her ivory dress-and-jacket ensemble and silver pumps strolling around N.Y.C. on May 2 as she is in her fuchsia Gucci frock and floral bolero at the Met Gala later that evening. 08 of 11 KEIRA KNIGHTLEY WENN; Humberto Carreno/Startraks To promote Last Night in N.Y.C., the made the rounds to television shows – wearing a mustard-and-grape combination with loafer pumps on The Today Show on the morning of May 9 and then visiting The Daily Show With Jon Stewart in a rosette-adorned Valentino frock. 09 of 11 SALMA HAYEK Venturelli/WireImage (2) was pretty as a picture to visit the “Il Mondo Vi Appartiene” exhibit in Venice, Italy, wearing a belted violet shirtdress and simple shoulder bag to tour the museum on June 1. But to attend a dinner for the exhibit that evening, the star turned the sex appeal up to 11 in a head-to-toe burgundy Gucci outfit. 10 of 11 KIM KARDASHIAN Fame; David Livingston/Getty The sexy ran errands in Beverly Hills May 11 in distressed jeans, a wrap sweater and one of her many Birkin bags. That night, she hit a party in a curve-hugging white sheath, strappy sandals and a glam down do. 11 of 11 JENNIFER GARNER Fame; John Shearer/Getty Busy mom to two is more often seen around town in an ensemble like this trousers-and-blazer look she wore in Beverly Hills April 20, but she cleans up nicely for an event, wearing a sleek black dress and snakeskin Coach clutch to a cocktail party that evening.