The 36-year-old's rep confirmed the news in a statement to Us Weekly, saying: "Charlize Theron has adopted a child. She is the proud mom of a healthy baby boy named Jackson.
While Charlize broke up with her long-term boyfriend, Stuart Townsend, in January last year, she revealed in August that she still wanted to be a mum, and that adoption was definitely on the cards.
"Why not? I'm open to everything in life," she told Germany's In Touch magazine, adding: "I want a baby. If it would happen tomorrow I would be very happy."
We're guessing that today's a very happy day in Charlize-land, then! Congratulations, girl!