Hollywood's Winter Birthday Babies!

Kourtney Kardashian and Scott Disick’s handsome little 1-year-old – his birthday was Dec. 14 – hit several milestones in his first year, including adding “Kim” to his vocabulary. “It’s like the third word he has ever said,” his mom told PEOPLE.

Though she only turned 5 on Dec. 1, Ben Affleck is already preparing for the dating years. “I’m…practicing the rocking-chair-and-rifle routine,” he joked on the Today show. Til’ then, dad and mom Jennifer Garner give their big girl free swing during a family getaway in Hawaii on Jan. 2.

“[She] is just so elegant and well spoken,” Angelina Jolie told Vanity Fair of her eldest daughter, who turned 6 on Jan. 8. Perhaps she’s learned from her multi-talented mom and dad?

Is he a football star in the making? Time will tell for Tom Brady and Gisele Bündchen’s baby boy, who celebrated his first birthday on Dec. 8.

From choosing her own outfits to singing alongside dad Joel Madden, this future star – who celebrated her 3rd birthday (on Jan. 11) with a star-studded bash! – is already showing her creative side.

To keep things fair, Rebecca Romijn and Jerry O’Connell vowed to never reveal the birth order of their twin girls, who turned 2 on Dec. 28. “We had this rule that we were going to treat them differently and dress them differently,” O’Connell told Scholastic Parent amp Child.

What a difference seven years makes! “The baby has become a boy,” Kate Hudson admitted to Extra of son Ryder, whose big day was Jan. 7. “Kissing him in front of his [friends], he’s starting to be like, ‘Mommm, stop!'”

With a rocker grandfather (Aerosmith’s Steven Tyler) and a rocker dad (Spacehog’s Royston Langdon), Liv Tyler’s son, who turned 6 on Dec. 14, shows plenty of stage presence in his spooktacular outfit while trick-or-treating with mom last October.

Forget terrible twos! It’s the energetic twos for Naomi Watts and Liev Schreiber’s little guy, who turned 2 on Dec. 13. One way to tire him out? Take him outside! “I know all the playgrounds very well,” Watts joked to USA Today.

Sandra Bullock’s 1-year-old “Cajun cookie,” whom she adopted last January, is the of her family. “He’s just perfect, I can’t even describe him any other way,” she told PEOPLE.

Daddy Diddy may be a busy man, but he tells PEOPLE that he always has time for his twin daughters (with ex Kim Porter). “When they tell me to sit down, everything else gets put to the back burner,” he confessed about his princesses, who turned 4 on Dec. 14.

Matthew McConaughey and Camila Alves’s almost New Year’s baby brought a sense of renewal to the couple when she was born on Jan. 3, 2010. “She came out and she gave us life so we named her Vida,” the proud papa told Jay Leno.

Whee! Fresh off her separation from husband Jordan Bratman, Christina Aguilera and her little boy took a ride down the slide at Mr. Bones Pumpkin Patch on Oct. 14. The singer told Marie Claire of her nearly 3-year-old, [he motivates] me to want to play and have fun.”