Pregnant Serena Williams Gracefully Dances in Her Met Gala Gown

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The mom to be had a Met Gala moment!

Serena Williams sashayed the night away.

"Become one with the Met Ball at night," Williams wrote alongside an Instagram video posted on Tuesday, where the Grand Slam champ is seen waltzing around with her jewel-hued dress' tail in hand.

WATCH: Serena Williams Shows Off Baby Bump With Fiance Alexis Ohanian at 2017 Met Gala

Showing off her growing baby bump, Williams arrived hand in hand with her fiance, Alexis Ohanian, the co-founder of Reddit. The tennis pro had (accidentally) announced she was pregnant with her first child last month when she shared a selfie of her burgeoning belly on Snapchat. During a sit-down with Gayle King at the 2017 TED Talks conference, Williams explained that the pic was posted my mistake.

"It was an accident," Williams stated. "I was on vacation just taking some time for myself and I have this thing where I’ve been checking my status and taking pictures every week to see how far along I’m going."

"On social media, you press the wrong button and [it's done]," she added. "Thirty minutes later I missed four calls and I'm like, 'That's weird.'"

WATCH: Serena Williams Shares Baby Bump Shot, Writes Heartfelt Message to Unborn Child

Since then, Williams has written a touching letter to her unborn baby and has fully embraced her maternity moments like a queen.

Watch below: