Serena Williams' daughter Alexis Olympia Ohanian Jr. learned she was going to become a big sister the same day the world did.

The tennis star announced her pregnancy at the 2023 Met Gala on May 1, debuting her baby bump on the red carpet with husband Alexis Ohanian. On May 5, Serena reflected on how she planned to break the news about baby No. 2 to their daughter, 5, in her first video shared on her newly launched YouTube channel.

"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," the 41-year-old said in the clip. "The reason I haven't told her is because she can't keep a secret."

At the Met Gala, Serena showcased her baby bump in a custom Gucci gown. She later shared an Instagram post containing pics of herself and her husband at the event, captioning it, "Was so excited when Anna Wintour invited the 3 of us to the Met Gala."

Alexis also shared pics of the two at the Met Gala on his own page, writing, "Mama (@serenawilliams) & Papa love this parenting-thing, so we're back at it and @olympiaohanian is gonna be the best Big Sister—she's been asking & praying for this for a minute."

Serena had talked about expanding their family in an August 2022 essay published in Vogue, during which the 23-time Grand Slam winner also announced she would be "evolving away" from tennis.

"In the last year, Alexis and I have been trying to have another child," Serena shared. "And we recently got some information from my doctor that put my mind at ease and made me feel that whenever we're ready, we can add to our family. I definitely don't want to be pregnant again as an athlete. I need to be two feet into tennis or two feet out."