Weeds star Mary-Louise Parker has adopted a baby girl from Africa, her reps confirmed exclusively to PEOPLE.

Parker, who was nominated for two Emmy awards Sunday night, was spotted with her new daughter over the weekend as they traveled to the show.

"Mary-Louise is such an incredible mom," says a source. "She couldn't be happier about this."

The actress's reps declined to reveal any more information about the adoption.

Parker, 43, also has a 3-year-old son, Will, with actor Billy Crudup, 39. The couple split before Will was born.