Star Tracks -- Tuesday, March 24, 2009

01 of 15

CROWD PLEASER

Samantha Who? star Christina Applegate makes her mark with fans outside New York's Ed Sullivan Theater on Monday before an appearance on The Late Show with David Letterman, set to air Wednesday. The actress's ABC comedy returns Thursday.

02 of 15

WEDDING PLANNERS

A newly engaged Calista Flockhart shows off her sparkler while out with fiancé Harrison Ford at a dinner Monday for Conservation International in Beverly Hills. The actor is on the board of directors of the eco-conscious nonprofit.

03 of 15

DOING THEIR PART

Glamming up for a good cause, expectant mom Nicole Richie and boyfriend Joel Madden cohost a fund-raiser Monday through their Richie-Madden Children's Foundation with Sony Cierge for UNICEF's Tap Project, which helps provide clean and accessible water to children around the world, at Hollywood hotspot MyHouse.

04 of 15

THE HONEYMOONERS

Still glowing from her weekend nuptials, Natasha Bedingfield is ready to get her honeymoon started Monday as she prepares for takeoff with husband Matthew Robinson (in green behind her) at Los Angeles International Airport.

05 of 15

FILM BUFF

Mary-Kate Olsen stands up for the arts, arriving at a cocktail reception celebrating the 2009 Tribeca Film Festival program on Monday at the W Hotel in Hollywood. The New York City film fest kicks off on April 22.

06 of 15

STROLL WITH IT

After a romantic Hawaiian vacation, Paris Hilton and boyfriend Doug Reinhardt strike out for the afternoon Monday in Hollywood, reportedly dining at Chin Chin followed by bowling at Lucky Strike Lanes.

07 of 15

OPEN-DOOR POLICY

She's ready to ride! Lindsay Lohan hops into a waiting car Monday after visiting a building in downtown L.A.'s fashion district and reportedly picking up some free clothing samples.

08 of 15

WHAT A RACKET!

That's not a tennis court! Venus Williams holds up traffic – and her racket – while filming a commercial Monday with fellow tennis star Andy Murray (not pictured) atop of cars in Miami Beach. The pros are in the Sunshine State to compete in the Sony Ericsson Open, which begins Wednesday.

09 of 15

GLOBAL AMBASSADOR

After screening his latest movie 17 Again in Australia, Zac Efron continues his international promotional duties – and gives a shout-out to Kanye West – after arriving Monday at Charles de Gaulle International Airport in Paris.

10 of 15

AT THE MOVIES

Though her latest film Management isn't out until May 15, Jennifer Aniston is bundled up and already back at work, reporting to the set of The Baster in New York Monday.

11 of 15

BRIDE-TO-BE

The secret is out but a newly engaged Calista Flockhart, who was surprised with a proposal by boyfriend Harrison Ford, keeps her engagement ring under wraps while out with son Liam, 8, (not pictured) in Los Angeles on Monday.

12 of 15

CROSSED SIGNALS?

Fist bump meet handshake! Jake Gyllenhaal and Amazing Race competitor Mike White seem to get their hand signals crossed after lunching together at the Brentwood Country Mart in Brentwood, Calif., on Monday.

13 of 15

READY, SET, WORK!

Mariska Hargitay, who had been sidelined with a collapsed lung for the past few weeks, makes a happy return to the set of Law amp Order: SVU on Monday in New York City.

14 of 15

BACKSEAT DRIVER

After helping his gal pal Eva Longoria Parker reportedly celebrate her birthday over the weekend in L.A., Mario Lopez pops up in New York City Monday, where he grabbed a cab at Rockefeller Center.

15 of 15

'COUGAR' PROWL

Courteney Cox Arquette makes one sexy statement as she continues to shoot her new show, Cougartown, in Los Angeles on Monday.