Did Serena Williams reveal the sex of Meghan Markle's baby?

Serena Williams, a new mom and friend to Meghan Markle, may have just smashed a very royal secret.

The Grand Slam-winning tennis pro sat down with E! News Wednesday and shared her perspective on motherhood, the challenges that come with balancing a baby and a career and some details on her friendship with another soon-to-be mom.

Williams told E! News that she often tells new moms to be kind to themselves.

"Accept mistakes and don't expect to be perfect," Williams said. "We put so much pressure on ourselves."

Williams even offered E! News the lesson she shared with an unnamed, pregnant friend.

"My friend is pregnant," Williams told E! News. "And she was like, 'My kid's gonna do this,' and I just looked at her and was like, 'No, she's not. No, you're not.'"

She added, "I had all those high expectations and then I had what I was going to do ... everything is not gonna go as planned. My whole life is so planned and this was the one time where it wasn't."

The 37-year-old tennis star was only trying to explain how she feels about setting realistic expectations of motherhood. But her specific use of the pronoun "she," has royal baby watchers abuzz. The "she" could mean a royal baby girl for the Duke and Duchess of Sussex.

Of course, Williams and the duchess are good friends. The duo met at the Super Bowl in 2010, reunited four years later at the 2014 Super Bowl and developed a bond through their lives in the limelight. The tennis champion attended Meghan's May 19 wedding last year and she also supported the launch of her first cookbook.

Although Williams didn't name Meghan specifically, royal fans feel the anonymous "friend" is likely to be her.

Williams knows a thing or two about managing constant media attention and being a first-time mom, so it makes sense that Meghan would lean on her for support.

The Duchess of Sussex's February baby shower in New York City included plenty of princess decorations. From pink cotton candy to blush-colored flowers and cookies, the celebration offered many clues.

Even still, the world won't know the baby's sex until Meghan delivers her first child sometime this spring.