Charlize Theron Adopts Second Child, a Baby Girl -- Find Out Her Name!

Congratulations are in order for the 'Mad Max' star!

Surprise! It's a girl for Charlize Theron.

The Mad Max: Fury Road actress has adopted a second child named August, her rep confirms to ET.

WATCH: Charlize Theron Invited President Obama to a Strip Club!

Theron, 39, worked with an adoption agency for six months before adopting the African-American girl in July.

August joins big brother Jackson, 3, who Theron adopted from her native South Africa in 2012.

Being a mom comes naturally for Theron, who knew she wanted to adopt from an early age. Last year, the Oscar winner reminisced to Vogue about a letter she wrote when she was 8 that read, "What I want for Christmas this year is for you to take me to the orphanage so that we can adopt a brother or a sister."

WATCH: Charlize Theron on Her Shocking Film Transformations

And now, Theron finally has a boy and girl!

The adoption came just one month after Theron split from Sean Penn. The actors had been dating since December 2013 and were reportedly engaged for about a year.