Star Tracks - Thursday, September 14, 2006

Mischa Barton is one busy lady, making several fashionable appearances while jet-setting around New York's Fashion Week on Wednesday. The actress (from left) showed off her floral instincts at a Saks Fifth Avenue bash, went a bit dotty at the Mischon Schur show and ended the night with a frill to check out Anna Sui's runway collection.

Meanwhile, Barton's former O.C. costar glams up the red – er, blue – carpet Wednesday at the Hollywood premiere of her romantic comedy The Last Kiss, costarring Zach Braff.

She's pop royalty: A tiara-bedecked Christina Aguilera gets her motor running at a London party celebrating jewelry designer Stephen Webster on Wednesday.

George Clooney sets his sights on Africa as he attends a private dinner to benefit the Save Darfur Coalition Wednesday in New York City. He was joined by two of his biggest fans: his parents, Nick and Nina.

Winona Ryder and Kate Moss – both of whom were once engaged to Johnny Depp – find common ground in their passion for fashion, shopping together at Marc Jacobs's New York City store on Wednesday.

Avril Lavigne, Heather Graham, Christina Milian and Petra Nemcova make a cozy front-row quartet at Fashion Week's Diesel show on Wednesday.

Sporting her new hair color and a fun leopard print, Jennifer Lopez gives her hand to main man Marc Anthony while out in Toronto on Wednesday. The couple is at the city's film festival to premiere their big-screen collaboration, El Cantante.

An undercover Lindsay Lohan gets caught in mod mode during a late night in New York City on Wednesday, a day after Jane Fonda told Access Hollywood that while her Georgia Rule costar is "so talented ... every once in a while a very, very young person who is burning both ends of the candles needs to have somebody say, 'You're gonna pay the piper, you better slow down.' "

Nicole Kidman, back from Rome after shooting an ad for a European television service, takes southern comfort in a two-hour yoga session at Sanctuary Yoga in Nashville on Wednesday.

Usher, who's starring onstage in Broadway's Chicago, nabs one of the best seats in the house Wednesday at Fashion Week alongside Hilary Duff (right) and TV host Maria Menounos. The trio took in Project Runway judge Michael Kors's show in New York City.

Hilary Swank looks – and likely smells – like a million bucks while promoting the launch of the new Guerlain fragrance Insolence at New York's Saks Fifth Avenue department store on Wednesday.

Liv Tyler is tickled pink during a photo shoot for Givenchy's new makeup line in Madrid on Wednesday. The actress has been a spokesperson for the French fashion house's cosmetics and fragrances since 2003.

Jessica Simpson gets the boot – in Chloe – during a solo dinner at Il Sole in Hollywood on Tuesday. The day before the singer lamented to Ellen DeGeneres that she feels she's "too hard to be in love with."

Ryan Cabrera and girlfriend Riley Keough (Lisa Marie Presley's daughter) get covered up in some interesting head gear for a stroll through Times Square in New York City on Tuesday.

Uma Thurman shows how she stands up to the test of time – pretty darn well! – at a Tag Heuer Party in New York City on Tuesday.