Theron, 39, adopted the African-American child in July. She was born in the U.S. and her name is August.
In April, Theron opened up about motherhood to W magazine. “…I do know that choosing to be a mom in my late 30s has been really great for me,” she said. “It’s given me perspective.”
The news comes just over a month after Us broke the news that Theron called off her engagement to Sean Penn, 54. The longtime friends — who went public with their romance in December 2013 — split shortly after attending the Cannes Film Festival in the south of France.
"Charlize wasn't responding to his calls and texts," an insider told Us. “She just cut it off."
As Us exclusively reported last year, Theron and the Gunman actor had plans to adopt together. Penn also wanted to adopt Theron’s 4-year-old son Jackson, whom she adopted from South Africa in 2012.
“Sean always knew that to truly earn a place in Charlize’s heart, connecting with Jackson was one of the most important parts,” a friend of Penn told Us at the time. “There is still talk of adopting again and giving Jackson a brother or a sister.”
Theron, who previously had a nine-year relationship with Irish actor Stuart Townsend, will next be promoting her upcoming film The Last Face, which Penn directed. The exes awkwardly had to reunite for reshoots in South Africa on July 29.