Partyhopper

We know it's really about the films, but we're keeping track of all the fetes happening in Cannes this year. Penelope Cruz will bring her A-game to the Hollywood Domino Tournament at the Riviera outpost of Soho House, where she'll raise funds for the Global Fund inspired by (RED). Sharon Stone will once again rule the auction block when she hosts the annual Cinema Against AIDS gala for amfAR, but this year the event relocates to the ultra-exclusive Hotel du Cap in Antibes. In 2007, Brad Pitt and Angelina Jolie were the center of attention during a party at night club Baoli. Last year, with twins on the way, they kept things low-key with an intimate dinner at Restaurant Tetou. The couple will return to Cannes next week for the premiere of Pitt's Inglourious Basterds--no word yet on their party plans.--Bronwyn Barnes

"I often I wear things that make me suffer for fashion, but not tonight!" Jessica Biel told us of the 3.1 Phillip Lim goddess gown she wore to a Cinema Society screening of her latest flick, Easy Virtue. What was it like playing dress-up for the movie, which is set in the Roaring 20's? "I felt like a glamor queen every day," she said. "The clothes from that period accentuated the waist and were easy-going on the hips. Everything was so feminine and beautiful." In the film, Biel plays an American woman who meets the parents (Kristin Scott Thomas and Colin Firth) of her new British husband (Ben Barnes) with less than favorable results, so when Jessica's real-life leading man arrived at the Gramercy Park Hotel for the after-party we just had to ask; Does she get on well with the Timberlake family? "Yeah, they are wonderful people," she replied.--Bronwyn Barnes

Celebrities gave reporters a run for their money at the annual White House Correspondents dinner on Saturday. "Hubby looked handsome as ever...even while frustrated that there was no signal to tweet!!!" Demi Moore (@MrsKutcher) Tweeted as the night wound down. Despite the technical difficulties, Twitter king Ashton Kutcher (@APlusK) did manage to get a message or two out. "Demi claims Obama gave her the 'what's up' smile," he teased. En route from Los Angeles to Washington, D.C. the day before the event, Miranda Cosgrove (@MirandaBuzz) provided breaking style news for her fashion-obsessed followers. "I decided to wear the gown for the dinner tomorrow at the white house yay! Haha," the iCarly star announced. Instead of Tweets, designer Donatella Versace took notes for her debut as a Huffington Post blogger. "The first lady looked beautiful. It was so great to see a President's wife in a hot pink dress, a jewelled necklace with a pink flower and purple eye shadow," Donatella wrote. "Great hair, great make-up — this is what we want to see: confidence." --Bronwyn Barnes

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The party for our InStyle Hair issue couldn't have come at a better time--after more than a week of rain, guests lined up to have their tresses tamed at the hair touch-up stations sponsored by the new line of John Frieda Root Awakening products. Ali Larter's solution to bad weather hair days? "A hat!" the Heroes star joked. In truth, Larter's secret weapon was celebrity stylist Harry Josh, who treated her to a blow out before she began her duties as the evening's host. Another perk the actress enjoyed--Marchesa designers Keren Craig and Georgina Chapman paid a visit to her room at the Hotel Gansevoort to help her pick out the perfect party dress. "It feels like I'm wearing a pink cloud," Larter told me as she spun around on the red carpet.

Once upstairs, I admitted to Samantha Who star Jennifer Esposito that I'd die to have her choppy bob. "I just tell my stylist, 'Cut this piece, now cut this piece!" she said of her very hands-on approach to gettng a cut and color. As a trio of models showed off some incredible Marchesa frocks--balanced atop pedestals on vertigo inducing Louboutin stilettos--Ari Graynor caught up with Spencer Grammer, Shannen Doherty kept a low profile on the patio and plenty of guests showed off their John Frieda hair makeovers. Thinking of getting a new 'do? Try on Hollywood's hottest hairstyles, get tips from the pros and shop for the latest products here. --Bronwyn Barnes

Where would the celebrities go for a little late night action after the Met Costume Institute gala wrapped up? Marc Jacobs invited the boldface names to the newly re-opened Monkey Bar, while New York nightlife queen Amy Sacco put the word out that the V.I.P.-friendly Bungalow 8 was open for business. Luckily, the fashion crowd doesn't tire easily, so most made time for both! At Monkey Bar, party girl Kate Hudson (in Stella McCartney) mingled with It model Agyness Deyn (in custom Burberry Prorsum) Rihanna removed the tie from her Dolce & Gabbana tux and slipped on a pair of sunglasses before facing the paparazzi. By the time Jessica Biel arrived with boyfriend Justin Timberlake, she'd swapped her voluminous Versace gown for a more manageable velvet Marc Jacobs party dress.

A while later, Rihanna, Kate and Agyness headed downtown to Bungalow 8, where they joined Josh Hartnett, Claire Danes and Eva Mendes. Katy Perry showed off her softer side in a Tommy Hilfiger silk dress. Even Marc Jacobs hit Bungalow after the action had tapered off at his own bash, proving that there's no such thing as too many after-parties.--Bronwyn Barnes

Last night, InStyle toasted May cover girl Jennifer Garner on her new role as an artist ambassador for Save The Children. The actress, who will speak out about the importance of early childhood education programs in the US and abroad, said she's always been inspired to help kids like the ones she grew up with in West Virginia. Speaking of children, just three months after welcoming second daughter Seraphina, Garner looked chic and svelte in an embroidered silk dress by Carolina Herrera. "The same designers still work on my body--designers who dress women," she told reporters about her post-pregnancy style. "I just need more options." Luckily, Jen's got stylist Rachel Zoe to call in anything she needs. "I was her first client," Garner pointed out when the subject of Zoe's transformation into a reality TV star came up. "I was there for the invention of 'Bananas!'"--Bronwyn Barnes