In a video posted to her newly launched YouTube channel this week, the tennis star discussed why she decided to announce that she and her husband Alexis Ohanian are expecting their second child at the 2023 Met Gala earlier this month. Serena revealed to viewers that she didn't tell her five-year-old daughter Olympia that she would become a big sister until the day of the annual fashion event. "Olympia does not know right now that I am pregnant, so the big reveal will be at the Met, and then before we leave, I'll tell Olympia."