Star Tracks: Tuesday, April 28, 2009

Obsessed star Beyoncé Knowles turns the streets of Vienna, Austria, into a catwalk Tuesday as she heads out to do some shopping in a fashion-forward ensemble of J Brand jeans, YSL shoes and a Valentino bag. Knowles is in Europe for her "I AM..." world tour.

Who's a big boy in the Big Apple? Ashlee Simpson-Wentz keeps a tender touch on her her little man, 5-month-old Bronx, during an afternoon out in New York City on Tuesday.

Leaving her little girls at home, a glowing Jennifer Garner hits the red carpet (in a Rachel Roy dress and Neil Lane jewels) for the L.A. premiere of her new flick, Ghosts of Girlfriends Past at Grauman's Chinese Theatre in Hollywood on Monday. The proud new mom to 3-month-old daughter Seraphina shared cell phone shots to pals on the red carpet, gushing, "She's so smiley!"

Need a lift? Jennifer Aniston offers her young costar a boost Monday as she continues to shoot her comedy, The Baster in New York City.

A Dolce amp Gabbana-clad Julia Roberts sets off a flashbulb frenzy as she arrives at the Film Society of Lincoln Center Gala Tribute honoring Tom Hanks Monday in New York City, where she dropped the F-bomb, telling her Charlie Wilson's War costar, "So, everybody f–ing likes you."

Rebecca Romijn and Jerry O'Connell take their little Dancing with the Stars fans – 4-month-old twin daughters Dolly Rebecca Rose and Charlie Tamara Tulip – to lunch Monday in Toronto, where Romijn is currently shooting a new movie.

Although the Mexico City premiere was postponed, Hugh Jackman revs up for a screening of X-Men Origins: Wolverine at the Harkins Tempe Marketplace theaters in Tempe, Ariz., on Monday.

School is in session for Hilary Duff on Monday, who drops by L.A.'s Normandie Avenue Elementary School to raise awareness for the Blessings in a Backpack food program. The actress has been an active supporter for the nonprofit, which donates food to needy students.

Perhaps satisfying her latest pregnancy craving, supermodel Heidi Klum keeps her cool with some frozen yogurt while out Monday in West Hollywood.

She's got his back! Selena Gomez and Taylor Lautner enjoy a little off-duty fun during a Saturday afternoon outing together in Vancouver. Lautner is in town filming the Twilight sequel New Moon, while Gomez is reportedly shooting Ramona and Beezus, based on author Beverly Cleary's popular children's book series.

While Katie Holmes played host at the Independent Filmmaker's dinner in New York City, hubby Tom Cruise is on daddy duty, enjoying a stroll with 3-year-old daughter Suri in Beverly Hills on Monday.

The cameras may have stopped rolling but Twelve costars Zoe Kravitz and Chace Crawford stick together, grabbing lunch Monday in New York. Recently, the Gossip Girl star has been spotted filming the drama in Central Park.

She's been exploring the city on her downtime – but Miley Cyrus knows when it's time to get to work! The Disney star (in DampG) says bonsoir to her fans at the premiere of Hannah Montana: The Movie Monday at Paris's Gaumont Marignan theater.

Kim Kardashian goes on a bender while demonstrating fitness moves during a pre-taped appearance for New York's Morning Show with Mike and Juliet on Monday, where she promoted her new workout video, Kim Kardashian: Fit in Your Jeans by Friday. The reality star's fitness segment airs Wednesday.

Showing off her sexy, slim figure, a dressed-up Megan Fox arrives at L.A.'s Shutters on the Beach hotel in Santa Monica to promote her action movie Transformers: Revenge of the Fallen on Monday.

Rihanna makes a perfect match with a young fan at the Reggae on the Hill festival Monday in Barbados's Farley Hill National Park. The RampB singer has been vacationing in her native country – and recently clocked some beach time with pal Katy Perry.