People.com Celebrity Star Tracks: Thursday, December 15, 2011 Kardashian steps out for son Mason's second birthday in L.A. Plus: Sofia Vergara, Katy Perry, Justin Beiber and more By People Staff Updated on January 24, 2022 01:04 PM Share Tweet Pin Email 01 of 15 B-DAY OUTING X17 Mom-to-be Kourtney Kardashian stays in step with boyfriend Scott Disick and birthday boy Mason, who celebrated his second birthday on Wednesday with a viewing of Disney on Ice at L.A.'s Staples Center. 02 of 15 GIGGLE FIT Jen Lowery/Splash News Online What's so funny? Sofia Vergara and Gerard Butler keep each other in stitches while taking a break from announcing the 2012 Golden Globe nominations Thursday at the Beverly Hilton Hotel. 03 of 15 THE CAT'S 'MEOW' David Wright/Startraks After being named one of 2011's Most Fascinating People, Katy Perry beams while aboard a trolley Wednesday during the unveiling of her new perfume, Meow!, at The Grove shopping center in L.A. 04 of 15 HOT WHEELS Splash News Online Justin Bieber gets behind the wheel Wednesday, heading out for a night of bowling at Lucky Strike in downtown L.A. 05 of 15 MOTHER LOVE Splash News Online Jessica Alba can't contain her joy during a holiday shopping trip with four-month-old daughter Haven in Santa Monica, Calif., on Wednesday. 06 of 15 EXTREME CLOSE UP! Landov Jude Law gets up close – and personal! – with Sherlock Holmes: A Game of Shadows costar Robert Downey Jr. Thursday during an appearance on The Graham Norton Show in London. 07 of 15 MAN ABOUT TOWN Pacific Coast News Back in London after his U.S. jaunt, Prince Harry leaves Jak's restaurant, his first stop during a fun Wednesday night out. 08 of 15 THE BELLY CURVE Jenny White/Broadimage Mom-to-be Hilary Duff shows off her growing baby bump in West Hollywood on Wednesday. 09 of 15 TO THE POINT Lluis Gene/Getty Sporting one of her favorite stage ensembles, Rihanna gives fans what they want at a concert in Barcelona, Spain, on Wednesday. 10 of 15 HOLLER IF YOU HEAR ME Splash News Online InStyle cover girl Jennifer Garner enjoys a day out with her bundle of joy, 2½-year-old Seraphina, in Santa Monica, Calif., on Wednesday. 11 of 15 SHOP TO IT Marcus/Splash News Online He won't be solo for long! The Bachelor's Ben Flajnik heads out on his own Wednesday while hitting up The Grove in L.A. 12 of 15 LEASH ON LIFE Allan Bregg/Splash News Online Blake Lively plays dog-sitter to beau Ryan Reynolds's mutt Baxter for the second day in a row Wednesday, taking the pooch for a walk during a break in filming Gossip Girl in New York. 13 of 15 STRIDE RIGHT INF Leaving main man Louis at home, a bundled-up Sandra Bullock exits her New York City hotel en route to a workout Wednesday. 14 of 15 MUSIC MATES 310pix.com Lady Antebellum's Charles Kelley and Hillary Scott have each other's backs while stopping by the New York City studios of Good Morning America Wednesday, where the country group – including Dave Haywood – performed. 15 of 15 ROLE CALL Kevork Djansezian/Getty Actresses Regina King and Judy Greer team up Wednesday to announce the Screen Actors Guild Award nominations in Los Angeles, where Greer earned a best cast ensemble nod for The Descendants.