Serena Williams may have let a top secret spill in an interview with E! When asked about advice she had for fellow parents, the tennis phenom said, “Accept mistakes and don’t expect to be perfect. We put so much pressure on ourselves.”

She then added, “My friend is pregnant, and she was like, ‘My kid’s gonna do this,’ and I just looked at her like, ‘No, she’s not. No, you’re not. She was like, ‘I need to talk to you about tips,’ because, yes, I had all of those high expectations.”

A friend, you say? Tell us more! While she didn’t say anything else, and certainly didn’t reference Meghan Markle or Prince Harry by name, she and Meghan are BFFs and Serena helped throw her baby shower. … and the speculation quickly exploded.

Now, U.K. bookies are slashing the odds of Meghan giving birth to a girl from 8/13 to 4/7.

“Royal punters are looking for any slip-ups and Serena might just have given them one. We’re taking no chances and have slashed odds on a girl as a result,” Ladbrokes spokesperson Alex Apati told People.