Star Tracks: Wednesday, August 17, 2011

After arriving in Glasgow, Scotland on a private train, PEOPLE cover star Brad Pitt returns to work Wednesday, shooting scenes for new movie World War Z.

A beaming Julia Roberts emerges from the water in Kauai, Hawaii, Tuesday, where the actress is vacationing with husband Danny Moder and their kids (not pictured).

What's she up to? A cheeky – and oh-so-stylish – Pippa Middleton gives a smile in central London on Tuesday.

And he's off! The Amazing Spider-Man star Andrew Garfield makes his way around West Hollywood Tuesday on his trusty Vespa.

What a cute pick-me-up! How I Met Your Mother star Alyson Hannigan gives her 2-year-old daughter Satyana a lift in Santa Monica, Calif., on Tuesday.

Can you spot the baby bump? All eyes are on mom-to-be Hilary Duff's burgeoning belly as she does a little shopping in Beverly Hills on Tuesday.

She's getting a kiss from The Dude! Jeff Bridges puckers up to The Big Lebowski costar Julianne Moore Tuesday night at the release of the Blu-Ray edition of the cult film in New York.

Alanis Morissette and husband Mario "Souleye" Treadway only have eyes for their precious cargo – son Ever, nearly 8 months – in Venice, Calif., on Tuesday.

Christina, is that you? Sporting oversized shades and a hat, Aguilera tries to keep a low-profile Tuesday while flying out of LAX with boyfriend Matthew Rutler.

Cowboys & Aliens star Olivia Wilde stays hippie chic while out and about in Santa Monica, Calif., on Tuesday.

Someone call for a superhero? Action star Chris Evans suits up to save the world Tuesday, reporting to the Cleveland set of The Avengers as alter ego Captain America.

Mom-to-be Rebecca Gayheart shows off her baby bump in blue while running Tuesday-afternoon errands in Los Angeles.

Good luck, Chuck! Ed Westwick works his smoldering good looks while sharing the spotlight with a four-legged friend on the N.Y.C. set of Gossip Girl Tuesday.

Ashley Tisdale sticks to her workout regimen, topping off her sporty look with a colorful cap and shades while heading to a West Hollywood gym on Tuesday.

Melissa & Joey star Joey Lawrence brings out the big guns – and his wallet! – to feed the parking meter in L.A. on Tuesday.