"I'm happy to confirm Serena is expecting a baby this fall," a rep for Williams said Wednesday, adding that she plans to return to the tennis circuit in 2018.
The Grand Slam winner, 35, teased the announcement on Snapchat Wednesday morning, posting a pic that was captioned, "20 weeks."
The photo was a mirror selfie, showing off her baby bump.
This is the second big announcement from Williams in the last few months.
This past December, she revealed on her verified Reddit account that she and Ohanian were engaged. Ohanian co-founded the user-generated news website in 2005.
"But by choice. Down on knee. He said 4 words. And I said yes," she wrote.