Serena Williams is a mom of two!
"Welcome, Adira River Ohanian," the new dad of two captioned a family photo, revealing their baby girl's name.
"I'm grateful to report our house is teaming [sic] with love: a happy & healthy newborn girl and happy & healthy mama. Feeling grateful. @serenawilliams, you've now given me another incomparable gift — you're the GMOAT," he wrote.
"Thanks to all the amazing medical staff who took care of my wife & our daughter 🙏 I'll never forget the moment I introduced @olympiaohanian to her baby sister."
He concluded the post with a quote, writing, "Your peace would have been like a river, your well-being like the waves of the sea."
The couple first revealed their baby news on TikTok Tuesday, where Williams shared a video that begins with the family sitting at a table, with daughter Olympia, 6 next month, leaning on Williams as Ohanian, 40, types on a laptop in front of them.
Williams then gets up and says she'll be right back, and returns with a tightly swaddled newborn. Settling back in between her husband and daughter, both lean into her, looking at the infant in her arms. At one point, Olympia leans in and plants a kiss on her baby sister's forehead. The video ends with Polaroid-style shots of the new family of four.
Speaking with PEOPLE about his recent partnership with Sharpie, Ohanian beamed at how fired up Olympia is about having a younger sibling.
"No one's more excited than her," the proud dad shared. "She's been wanting this. She's been praying and asking about this for quite some time, so she's very ready."
Ohanian also opened up about feeling more confident about welcoming baby No. 2 than his first go around as a dad.
"We're not first-time parents anymore. I feel more confident about having a newborn, all of those things that I just had zero confidence about with Olympia because I’d never even been around babies at that point in my life," he explained.
"We're also obviously taking every precaution and doing everything we can to make sure everything goes smoothly for Serena."