Serena Williams pens letter to future baby: 'You taught me the true meaning of serenity and peace'

— -- Serena Williams announced her pregnancy last week, and the soon-to-be mom already has sweet words for her future child.

"My dearest baby, you gave me the strength I didn’t know I had," the 35-year-old tennis superstar wrote in the caption. "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."

The post also coincided with the birthday of Williams' fiance, Alexis Ohanian, who is the co-founder of Reddit.

Williams concluded the sweet note with her new signature: "Your Mommy."