“I can't wait to meet you. I can't wait for you to join the players' box next year,” the post continued. “But most importantly, I am so happy to share being number one in the world with you.... once again today. On @alexisohanian bday. from the world's oldest number one to the world's youngest number one. -Your Mommy."
Williams is taking her maternity leave from the sport after announcing her pregnancy. She plans to return to tennis in 2018.