"My Dearest Baby, You gave me the strength I didn’t know I had," Williams wrote in a sentimental Instagram post on Monday, alongside a selfie showing her growing baby bump. "You taught me the true meaning of serenity and peace. I can't wait to meet you. I can't wait for you to join the players' box next year. 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."
And it looks like Williams and Ohanian, the co-founder of Reddit, are celebrating his birthday in style. The tennis star has been sharing pics of her enviable tropical location, and last week, shared an adorable photo of her fiance carrying her on the beach.