It was announced in April that Serena Williams and fiancé Alexis Ohanian were expecting a baby, with the Women's tennis number one seed posting a photo of her 20-week bump to Snapchat.
Williams and her fiance, Reddit co-founder Alexis Ohanian, have since posted images of themselves to showcase their elation with all of this good news.
The 35-year-old added that she and Venus, as well as their half-sisters Yetunde, Lyndrea and Isha Price, have a tendency to use female pronouns in conversation.
Venus then added that all of the aunts were vying for their sister to name the baby after them.
"I think the surprise of knowing what you are going to have on that very special day you give birth is probably the best surprise you can ever have", the pregnant tennis champ wrote on Instagram Thursday morning.
Venus made the slip during a television interview on Wednesday after winning against Japan's Kurumi Nara in Paris, a match her sister came to watch.
She said she had been joking with her sisters about naming the baby after them.
But hold up: Serena isn't ready to confirm that she has a baby girl on the way just yet. "I did not grow up with any brothers, only sisters and we all say "she" more than "he". "It was an accident", she told Gayle King at the 2017 TED Talks conference, clarifying why the pic was deleted shortly after it was posted.
In Paris, her coach Patrick Mourataglou said Serena could be back as soon as the Australian Open.
"I didn't tell a lot of people, to be quite honest, and I'd been saving it", Serena continued. "On social media, you press the wrong button and [it's done]". My phone doesn't ring that much, and 30 minutes later, I'd missed four calls, and I'm like, "That's weird".