Serena Williams reveals she is 20-weeks pregnant

Serena Williams (left) and Alexis Ohanian. (Reuters)

Serena Williams announced she's expecting a baby with fiance Alexis Ohanian.

(Snapchat)

The tennis star, 35, shared a picture of her growing baby bump on Snapchat with the caption "20 weeks."

An error occurred while retrieving the Instagram post. It might have been deleted.

Williams and her Reddit co-founder fiance, 33, announced their engagement in December.