Serena Williams can't wait to be a mom. The all-star tennis player took to Instagram to share a selfie of her growing baby bump and penned a heartfelt note to her unborn baby. She writes, "My Dearest Baby, You gave me the strength I didn't know I had...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.' Williams traveled to Mexico with fiancé Alexis Ohanian shortly after she announced her pregnancy on Snapchat.