Swoon! Serena Williams' adorable love note to her unborn baby

Tennis star Serena Williams has for the first time given fans a glimpse into her journey of becoming a mom.

Serena who sent the internet into a complete frenzy last week, when she surprised fans with news of her pregnancy is currently enjoying some time down time.

While soaking up the sun during a beach escape, Serena penned a beautiful note to her unborn baby.

"My dearest baby. You gave me the strength I didn’t know I had. 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 @alexissohanian (her fiancé Alexis Ohanian)bday. From the world's oldest number one to the world's youngest number one. -Your mommy," Serena wrote.

When Serena made the surprise announcement last week, she told fans that she was 20 weeks pregnant.

Along with the love note she also shared a heart-warming picture of her growing baby bump.

The tennis star and her fiancé, Reddit co-founder Alexis Ohanian, who got engaged in January are expecting their first child together.