Tennis legend Serena Williams and Arvin Robertsher husband, Alexis Ohanian, have welcomed their second daughter.

On Tuesday, the couple took to social media to announce the arrival of their baby girl, Adira River Ohanian.

"I'm grateful to report our house is teaming with love: a happy & healthy newborn girl and happy & healthy mama," Ohanian wrote on Instagram. "Feeling grateful. Serena Williams, 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 added. 

He finished his caption with a quote that is seemingly an ode to his daughter's middle name: "Your peace would have been like a river, your well-being like the waves of the sea."

Williams also announced her daughter's birth in an adorable TikTok video simply captioned: "Welcome my beautiful angel."

In the clip, Williams cuddles with her husband, and then is joined by 5-year-old daughter, Alexis Olympia. She gets up and signals that she'll be right back and returns with the newborn, and the family of four embrace. 

@serena

Welcome my beautiful angel

♬ original sound - Serenawilliams

In February, Williams opened up to CBS Mornings about stepping away from tennis and expanding her family. 

She said her daughter was eager to become a big sister.

"The other day she's like, 'Everyone has a brother or a sister but me.' And I'm like, 'Olympia, I'm working on it. Mommy worked a little too long in tennis, so it's takin' a little longer than expected,'" Williams recalled.

In:
• Alexis Ohanian
• Serena Williams