Star Tracks: Monday, January 31, 2011

Family time! Kourtney Kardashian leads the way while Scott Disick totes 13-month-old Mason for a walk through Los Angeles on Saturday.

Who's the Lakers biggest fan? Zac Efron, who gives a fist-pumping show of support Sunday for the home team, who lost 109 to 96 to the Boston Celtics.

Matt Damon shows his true colors – Boston all the way! – at the Staples Center Sunday, where his hometown Celtics bested the defending champion Los Angeles Lakers.

He's just too doggone cute! Jake Gyllenhaal joins a pal and his pooch, Atticus, for a hike along Mulholland Drive in Los Angeles on Saturday.

Well-tressed star Seth Rogen presents pal (and Pineapple Express costar) James Franco with the outstanding performance of the year award for 127 Hours at the 26th annual Santa Barbara Film Festival on Saturday.

Ashton Kutcher and Demi Moore make a fashionable arrival at the Colcci fashion show – where the actor walked the runway! – during Sao Paolo Fashion Week on Sunday. "Loving being back in Brazil," Moore Tweeted.

Britney Spears is escorted down the aisle of the Spanish Monastery in Miami as she fulfills her bridesmaid role at her friend and assistant Brett Miller's wedding.

Matthew McConaughey takes advantage of the warm weather, running along Zuma beach in Malibu.

One of these things is not like the other.... Oscar co-host Anne Hathaway has fun experimenting with patterns (check out those ruffled cropped pants!) at while promoting her upcoming animated flick Rio Friday in Los Angeles.

Front and center for the Lakers game in Los Angeles, Khloe Kardashian (left) and Nicole Richie create their own picture-perfect memory!

Taylor Swift and her band celebrate her #1s and her top sales at the "Heavy Metal at the Hard Rock" party in Nashville, Tenn., Friday.

Look who's smiling! With her treatment complete, a sunny Demi Lovato steps out Friday in Santa Monica, Calif.

Looks like the secret's out! Mom-to-be Kate Hudson shows off her growing bump Friday while out and about in Paris.

Neil Patrick Harris and partner David Burtka enjoy a night off from their newborns Thursday as they toast the opening of the Art Los Angeles Contemporary, an art fair in Santa Monica, Calif.

With her Sharpie in hand, Keira Knightley greets fans outside London's Comedy Theatre on Friday following a performance of her new play, The Children's Hour.

Flame-haired vixen Christina Hendricks lends her face – and famous curves! – to a sweet pop-up shop opening for chocolatier Godiva Friday in New York.

Brooke Shields aims high during a visit to Sirius XM Radio Friday in New York, where she was promoting her limited engagement (Feb. 1 – 12) show, In My Life, at the fabled Feinstein's at Loews Regency.

Kelly Rowland takes an elegant stand (in a Nicole Miller gown) Thursday at the MTV Staying Alive bash celebrating the achievements of MTV exec Bill Roedy. "I am honored to have been a part of his celebration," the singer Tweeted after the event.