Serena Williams. Photo: Serena Williams/instagram

Serena Williams is helping families in need.

On Wednesday, the tennis superstar, 42, revealed she donated extra breast milk that she had leftover from a recent trip to New York.

“After going through a screening I was able to donate it instead of taking the milk home,” Williams captioned an Instagram video. “I know so many amazing women that adopt or are unable to make milk. It felt amazing. BTW Someone out there is getting some super soldier milk. 🤭.”

In the clip, the former athlete’s voice is heard off-camera as she opens a freezer, displaying multiple packets of breast milk.

Williams said she was “really excited” to donate the breast milk “to people who really need it.”

Before closing the freezer door, she added, “It’ll be anonymous, but super excited to just help in some way.”

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“Some kids backhand just got stronger,” one Instagram user joked in the comments section.

Others praised her contribution. “My baby is adopted and ended up having severe dairy allergies, so we relied on donor milk. It was such a gift to us and I’m always so grateful when I think about it!❤️,” another user wrote.

Williams and her husband, Alexis Ohanian, welcomed their second daughter, Adira River Ohanian, in August. The couple’s first born, Alexis Olympia Ohanian Jr., who is called Olympia for short, was born on Sept. 1, 2017 in West Palm Beach, Florida.

Alexis Ohanian Sr., Serena Williams, Alexis Olympia Ohanian Jr., and Adira Ohanian.Alexis Ohanian Sr. Instagram

Before their youngest daughter’s arrival, Ohanian, 40, spoke exclusively to PEOPLE about how he felt “confident” about expanding his family with the tennis champ.

“We’ve got everything basically good to go,” Ohanian said over the summer.

Serena Williams Previews the Sweet Moment She Told Daughter Olympia, 5, That She Is Pregnant: Watch

“I think I’ve I’ve definitely forgotten what it’s like to have a new one around, so it might be a rude awakening, maybe literally,” he said with a laugh. “But right now, we’re excited.”

Serena Williams.Al Bello/Getty

Before announcing her second pregnancy, Williams said she would be stepping away from tennis in the Sept. 2022 cover of Vogue.

In her essay for the outlet, she shared that Olympia had expressed that she wanted to be a “big sister” when she grew up.

“I’m the youngest of five sisters myself, and my sisters are my heroes, so this has felt like a moment I need to listen very carefully to,” she said, explaining her decision to evolve away from tennis to focus on growing her family.