Serena Williams reveals she's pregnant in sexy swimsuit selfie!

Woah baby!

Serena Williams revealed on Snapchat that she's expecting her first child with fiancé Alexis Ohanian! The 35-year-old tennis superstar showed off her teeny, yet adorable, baby bump in a bright yellow one-piece swimsuit while revealing she's "20 weeks" along in the caption.

Her soon-to-be husband, who is also the co-founder of Reddit, proposed to her last December after two years of dating during a vacation in Rome, where the couple first met. They revealed the news on -- where else -- Reddit!

She then took to the online forum again to show off her sparkly engagement ring a couple of weeks later in an adorable snap with her man titled "Engagement shoe game." The two dressed to impress as she rested her hand on his chest, showcasing her huge rock!

They're currently enjoying time with each other on vacation at an undisclosed tropical location (possibly to celebrate the baby?!) and have been posting photos non-stop.

In one romantic snapshot, the pair sported big smiles on the beach as Ohanian picks her up. They rocked casual outfits and looked like they were having a blast.

The baby news is definitely exciting for the happy couple, since Serena just scooped up her latest tennis title in January 2017 at the Australian Open. And if our math is correct -- she may have already been pregnant at the time, making her victory even sweeter in retrospect.

Congrats to the happy couple!