Serena Williams, Fiancé Alexis Ohanian Welcome Baby Girl!

Serena Williams and Alexis Ohanian are officially parents.

On Friday, Williams, 35, gave birth to a baby girl at a hospital in Palm Beach, Florida, a source told Us Weekly. Her sister, Venus Williams, also confirmed the news to ESPN. "I'm super excited," the tennis player said. "Words can't describe."

The couple has yet to share photos of their first child, but fans are no doubt eager to see the baby girl. Williams caused a frenzy earlier this year when she accidentally announced her pregnancy on SnapChat. In her post, she was wearing a yellow one-piece swimsuit that showed off her baby bump, revealing in the caption that she was 20 weeks pregnant. She immediately deleted the post, but it was already too late.

Williams later addressed her mistake and clarified that she had only announced the pregnancy a few days earlier than planned. "On social media, you press the wrong button and... 30 minutes later I missed 4 calls and I'm like, 'That's weird,'" Williams told Gayle King at a TED Talk (via Daily News) following her accidental announcement. "But it was a good moment. I was only going to wait 5 or 6 more days."

Meanwhile, Williams and Ohanian have been preparing for the arrival of their child over the past several months. Ohanian, co-founder of Reddit, has received a lot of parenting tips online. In fact, he previously shared his favorite piece of advice.

"My favorite (tip) is to sleep with a blanket for like a month before the due date so you get your dad scent all over it, and then wrap the baby in it once it shows up, so they're not just immediately bonding with mom, but also getting a bit of dad," he said during an appearance on "Today."

Like her husband, Williams also took to Reddit to ask for advice as to when she should prepare her hospital bag and what she needs put in there. Fortunately, a number of moms quickly responded to her inquiry with practical advice. They suggested that she bring Bluetooth speakers, hair ties, extra pillows, comfortable blankets, towels, toiletries, nursing bras, phone charger, comfortable clothes and her favorite snacks.

But though she's excited about their bundle of joy, Williams also previously admitted that she has never been around babies. She even joked that she needed baby 101 class, but it was only offered to daddies thus Ohanian might be more knowledgeable than her when their baby arrives. As such, she said she has a lot of respect for all mothers and thinks of her pregnancy as something that makes her feel like a real woman.

"I have so much respect for so many women [for giving birth]," Williams said (via Entertainment Tonight). "I am about to be a real woman now, you know? It's going to be something incredibly impressive to go through."

Do you have parenting tips for first-time parents Williams and Ohanian? Share them in the comments section below.