FIRST PIC: Charlize Theron Steps Out With Baby Jackson, 4 Months

Us Weekly

Have baby, will travel!

Charlize Theron hit her local post office in Los Angeles on Tuesday with a very precious package: Her newly adopted son, Jackson!

Theron, 36, kept her little boy completely covered up in a carrier and blanket as she headed in for her errand; the globetrotting "Snow White and the Huntsman" star was at the post office in order to get a passport for her baby boy.

PHOTOS: Charlize's hottest looks

The South African beauty surprised fans everywhere when she announced her bundle of joy to Us Weekly on March 14. A Theron pal tells Us that she named the 4-month-old African American infant herself. "She really loves the name!" the pal explains.

PHOTOS: Stars who've adopted

The Oscar winner (who hasn't seriously dated since she and beau of nine years Stuart Townsend split in early 2010) spent much of 2011 going through the adoption process. "It's been a long time in the making," another insider said.

And, indeed, in 2010, Theron admitted: "I know I want to raise a big family."

PHOTOS: Cutest celeb babies ever

And Jackson's passport will definitely come in handy. "Jackson will go wherever she goes," the first source says. "Charlize will be a full-time mom!"

RELATED ON WONDERWALL & MSN:

See which celebs are expanding their families this year

Hollywood's weirdest celeb friendships

Celebs out and about lately