The proud girl dad also shared the moment Olympia, 5, met her little sister for the first time
Alexis Ohanian is joyfully revealing his new title: girl dad of two.
"Welcome, Adira River Ohanian," he wrote alongside the photos.
"I'm grateful to report our house is teaming [sic] with love: a happy & healthy newborn girl and happy & healthy mama," Ohanian shared, adding, "Feeling grateful."
Addressing his tennis star wife, 41, he wrote, "You've now given me another incomparable gift — you're the GMOAT."
"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 said, also sharing photos of the moment between the two sisters.
Concluding his post, he wrote, "Your peace would have been like a river, your well-being like the waves of the sea."
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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 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. The video ends with Polaroid-style shots of the new family of four.
"Welcome my beautiful angel," she captioned the TikTok.
Speaking with PEOPLE in June, Ohanian was looking forward to getting the hang of having a newborn in the house again.
"I think I've I've definitely forgotten what it's like to have a new one around, so it might be a rude awakening, maybe literally," he said with a laugh. "But right now, we're excited."
Ohanian also talked about feeling more confident the second time around, noting, "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."
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