Star Tracks: Monday, January 11, 2010

New dad Matthew McConaughey lets his shirt do the talking Saturday, sporting a top that pays homage to his new baby girl Vida, while working out around his Malibu neighborhood.

Katy Perry only has eyes for fiancé Russell Brand during a shopping trip Saturday in London – where the singer showed off the diamond ring her comedian beau gave her during a trip to India on New Year's Eve.

See how the romantic duo went from flirting to engagement – in three months!

Less than a month after giving birth to son Mason Disick, new mom Kourtney Kardashian brings her baby boy out for a family gathering – which included Aunt Kim (not pictured) – in Los Angeles on Sunday.

Kristin Cavallari celebrates her 23rd birthday Saturday at Eve Nightclub in Las Vegas. At her bash, The Hills baddie raved about her obsession with another reality show – Jersey Shore. "Is that bad that I love it?" she told PEOPLE.

Things are heating up for family man Hugh Jackman, who bares his buff bod poolside during a family vacation in Rio de Janeiro on Saturday.

These two are inseparable! Ashley Tisdale gives her BFF Vanessa Hudgens a tight squeeze at her sister Jennifer Tisdale's baby shower in Beverly Hills on Saturday.

Megan Fox keeps warm in style while filming Passion Play with Mickey Rourke, who plays a down-on-his luck trumpeter helping Fox's girl in trouble with the mob, in Albuquerque, N.M.

Jennifer Lopez wears her heart on her chest while shopping in Miami Beach. The singer-actress, who recently made waves with her nearly-naked catsuit, next stars in The Back-Up Plan about a woman who conceives twins via artificial insemination.

After paying a virtual visit to the The Jay Leno Show Monday, Jersey Shore's Nicole 'Snooki' Polizzi puts her best "pouf" forward Friday as she prepares to do the weather on New York's WPIX morning show.

In celebration of Elvis Presley's 75th birthday on Friday, Priscilla and Lisa Marie Presley – with her children Riley, 20, and Benjamin, 17 – greet fans at the King's former homebase of Memphis, Tenn. The family made an appearance at his Graceland estate for a cake-cutting ceremony to mark the occasion.

Country star Garth Brooks joins Jewel and her husband, rodeo star Ty Murray, to announce a new partnership between Professional Bull Riders, Inc., and Brooks's Teammates for Kids Foundation in New York City on Friday. The two groups hope their collaboration will raise $1 million for children in need this year.

Look who's having a fun girls' night out! Whitney Port and Brooke Shields laugh it up while serving as hosts for the LG Lotus Elite launch party at The Palms Place in Las Vegas on Thursday.

Sporting matching pairs of shades from the singer's Melodies sunglasses line, Ellen DeGeneres and Mary J. Blige celebrate the RampB diva's 39th birthday while taping an episode of The Ellen DeGeneres Show airing on Monday.

With his ex-wife Kate Gosselin sporting buzz-worthy new blonde locks, former reality TV dad Jon Gosselin makes some changes of his own, working on his physique at a hotel gym in Los Angeles on Friday.

Nick Jonas waves goodbye after co-hosting Live! With Regis and Kelly Friday in New York. Next up for the youngest JoBro: He and his new band, Nick Jonas amp The Administration, will perform during the Critics' Choice Movie Awards on Jan. 15.