Serena Williams is pregnant! The tennis star revealed the news on Snapchat with a sexy baby bump photo.

Williams posted the picture below on the social media service. She added the caption, "20 weeks." So the baby will likely arrive in late August or early September.

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So far Williams has not slowed down much during her pregnancy. She actually won the Australian Open tennis major in late January, when she was about two months along.

Serena Williams Baby Bump Serena Williams debuted her tiny baby bump on Snapchat.

Serena Williams got engaged to Reddit co-founder Alexis Ohanian in December. They have reportedly been together since late 2015. Just a few days ago, she posted a sweet photo of the duo from their Easter vacation.

"They laugh non-stop and that really fuels their relationship," a source told E! News of the couple. "They are on the same page in life and are excited to start something great with each other."

It's unclear if this pregnancy will affect the couple's wedding plans. But Williams said in January that she wasn't rushing down the aisle.

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"It feels good," Williams said of being engaged. "I really haven’t thought about it too much, because I wasn’t even really gonna think about it until after the [Australian Open] tournament. So, I just keep saying, ‘February, I’ll start looking at the bigger picture of my life.’ But right now, I’m just so focused that this is all I can think about."

This will be the first child for Serena Williams. But she has been open in the past about wanting kids. During a Twitter Q&A in 2014, she told a fan that she "desperately" hoped to start a family someday.

Serena Williams Engagement Ring Serena Williams and Alexis Ohanian got engaged in December.

Williams similarly told Glamour last year that she "definitely" wanted to have kids. But she also hinted that she would wait a bit longer.

"That's something I've always wanted since as long as I could remember," she said. "And the older I get, the more I'm like, 'I'm too young!'"

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She continued, "I was just joking with [sister] Venus [Williams] about this yesterday and saying 'I'm far too young!' Hopefully I'll be able to mature one of these days, get serious, and at least have them pretty fast."

What do you think of Serena Williams' baby bump photo? Let us know your take in the comments section below!