HANOI — Actor Angelina Jolie finalized the adoption of a Vietnamese orphan on Tuesday, adding a fourth child to her family, according to the US-based adoption agency that organized the process.

Jolie has remained out of public view since arriving in southern Ho Chi Minh City last Wednesday to pick up the 3 1/2-year-old boy from an orphanage and traveling to Hanoi on Monday to complete the adoption.

The boy’s birth name is Pham Quang Sang but Jolie has renamed him Pax Thien Jolie, a name that combines the Latin word for peace and the Vietnamese word for sky or heaven.

"The Vietnamese authorities had already cleared the adoption, and the US Embassy approved the adoption on Tuesday," said spokeswoman Laura Feragen on behalf of Philadelphia-based nonprofit agency Adoptions From the Heart.

"They will pick up Pax’s visa on Wednesday and they are free to go home," she said.

Oscar-winning Jolie, 31, traveled to Vietnam with her 5-year-old son Maddox, who was adopted from Cambodia, and 2-year-old sister Zahara, adopted from Ethiopia.

She also has a biological child Shiloh Nouvel with actor and companion Brad Pitt.

An online newspaper on Tuesday reported that as Jolie finalized the paperwork, her adopted sons played and communicated by sign language in the lobby of the historic luxury Metropole Hotel in Hanoi.

"Maddox and Sang played in the lobby and they seemed to get along really well," the online VNExpress quoted an unidentified hotel staff member as saying. "They don’t understand each other’s language, but they used sign language to communicate."

Completion of the adoption came as Hollywood trade paper Daily Variety reported on Tuesday that Jolie has been cast in her next movie, an action film called "Wanted," set to begin shooting in Eastern Europe in May. Variety said she will play an assassin who teaches the ropes to an aspiring hitman.

Jolie, her family and their assistants arrived in Hanoi on Monday and checked into the white facade Metropole Hotel, which opened during French colonial rule in 1901. It has rooms named for Charlie Chaplin, an early Hollywood star, and the English author Graham Greene.

During Tuesday’s lunch hour, a silver minivan with darkened windows — thought to be carrying Jolie — drove quickly into the Rose Garden Tower, one of two US Embassy buildings in the Vietnamese capital. The vehicle left about 35 minutes later.