By Jason Lynch
March 19, 2007 12:00 PM

Wherever Angelina Jolie and Brad Pitt travel, they like to meet the locals up close. So when the couple stopped by an orphanage in Vietnam’s Ho Chi Minh City the day after Thanksgiving, it seemed a typical goodwill gesture. Mixing easily with the children, they gave out candy and balloons. At one point, Jolie “sat down to play with the kids and helped them assemble puzzles,” says a source. “She was very friendly to the orphans.” Few onlookers knew they were among movie stars. Recalls one: “They looked like backpackers.”

But they were hardly tourists. For months the couple have been preparing to find a sibling for Maddox, 5, Zahara, 2, and 10-month-old Shiloh, a “process that began shortly after Shiloh was born [last May],” says a source. It wasn’t until March 2 that a Vietnamese official revealed that Jolie, 31, had filed preliminary papers to adopt a child—according to one adoption worker, “a boy between the ages of 3 and 5.” But the source close to Jolie says there are still a few more steps before welcoming a new family member. “It’s wonderful that people are excited about it,” says the friend. “But she is only at the beginning of a very comprehensive and detailed process.”

In Vietnam that process includes several reports by authorities, a home study and a background check—which can take between three months and two years. Because it’s difficult for unmarried couples to adopt jointly in Vietnam, Jolie is applying as a single parent. As for the child’s identity, says the source, “she is simply waiting for further information” from officials about a potential adoptee.

What’s never been in doubt is the couple’s desire to expand their family—and to adopt internationally. “Having a child in any way is a very special thing,” Jolie told PEOPLE in ’05, “but there’s something about making a choice, traveling somewhere and finding your family and recognizing each other.” Why Vietnam? Jolie has traveled extensively in Southeast Asia and has visited the country at least twice. After adopting Maddox from Cambodia and Zahara from Ethiopia, she mused to Good Morning America in December that it might be a good idea to “balance the races so there’s another African person in the house for Z [and] another Asian person in the house for Mad.” As for Pitt, he told PEOPLE in January that he and Jolie are “of course” interested in more kids.

As they navigate adoption red tape, the family of five has been happily settled in New Orleans since January, where Pitt, 43, has been filming the romance The Curious Case of Benjamin Button. Locals frequently spot them strolling through the French Quarter, buying baby clothes (a “Dirty South” T-shirt for Maddox, a black dress for Zahara and a hot-pink onesie for Shiloh) and dining out with Button costar Cate Blanchett. Soon they’ll return home to L.A., where Pitt will resume filming. Jolie, meanwhile, continues to speak out about the atrocities in Darfur (see box) as she eagerly awaits the phone call that will enable her to officially add to her brood. The good news can’t come soon enough. “I just want more kids,” she told PEOPLE recently. “I’m having a great time.”

See the complete celeb bio of Angelina, plus up-to-the-minute news and photos, at PEOPLE.COM/ANGELINA_JOLIE