Superstar couple Angelina Jolie and Brad Pitt are reportedly set to adopt another child: this time a little boy from Ethiopia.

"Angelina was pretty far along in the process of adopting a beautiful baby that captured the couple’s heart when she and Brad got the surprise of their life and found out they were expecting," a source tells OK!.

Angie and Brad, who are expecting fraternal twin girls this summer, are already parents to Maddox, 6, Pax, 4, Zahara, 3, and a 2-year-old biological daughter, Shiloh. If the new adoption goes through, the Jolie-Pitts will have a total of 4 girls and 3 boys, of which three would be biological children and 4 would be adopted.

"Angie and Brad have wanted an African boy for the last couple of years,” the source told OK!. "They were initially going to have that adoption follow the addition of Pax last year, but that all changed when Angie got pregnant with twins last fall."

Angie, 33, had suggested in previous interviews that she wanted an even distribution of nationalities and backgrounds in her multicultural family. And since Maddox, who's Cambodian, got a little Asian playmate when the couple adopted Pax from Vietnam in 2007, adopting a playmate for Zahara (who was herself an Ethiopian orphan) may make sense to the Jolie-Pitts.

Last year, Angelina discussed the importance of keeping a balanced family as well as how to balance the way their children view the Jolie-Pitt clan. "The questions are more when you have a mixed-race family," she said. "Do you balance the races so there's another African person in the house for Z? So there's another Asian person in the house for Mad? Shiloh has Brad and I she can look at."

Of her biological daughter, Jolie has said: "Shiloh looks like Brad. It’s funny because she’s almost going to be the outcast in the family because she’s blonde and blue-eyed." Of her adopted children, Angie said: "I felt so much more for Madd, Zahara and Pax because they were survivors. Shiloh seemed so privileged from the moment she was born. I’m conscious that I have to make sure I don’t ignore her needs, just because I think the others are more vulnerable."