The Daily Star reports that the pair have signalled their intention to add a second Ethiopian child to their family.
Their 6-year-old daughter Zahara previously lived in the poorly-developed eastern African nation.
"They are really excited about it," a source claimed. "Brad and Angie made a promise to Zahara years ago that they would adopt another child from the region so she could have a sibling to relate to."
The insider added: "Also, seven has always been Brad's lucky number. He and Angelina think it would bring them luck and happiness."
The couple also parent Cambodia-born Maddox, 10, and 7-year-old Vietnamese son Pax, as well as their own children, 5-year-old Shiloh and 3-year-old twins Knox and Vivienne.
Speculation over a seventh child has been mounting all year, with Jolie insisting that she will not rule out another adoption.