"I feel like we need to bring domestic abuse and financial abuse out of the shadows and into public conversation," says Serena Williams

Serena Williams is using her platform for good, once again — and this time, the issue hits close to her heart.

The 23-time Grand Slam champion stars in the latest PSA for The Allstate Foundation Purple Purse program, which highlights the seriousness of financial abuse.

The video — called “Signs” — aims to increase the education and awareness of financial abuse as part of a wider campaign aimed at increasing public engagement with the issue.

“I feel like we need to bring domestic abuse and financial abuse out of the shadows and into public conversation,” Williams, who has worked with Purple Purse for several years, tells PEOPLE. “I know it’s an uncomfortable conversation, but we need to make it more public. That’s the only way that, together, we can end abuse against women and other people in relationships.”

Williams says she was surprised to learn that financial abuse is present in 99 percent of domestic violence situations. It forced her to ask questions including “How can I help?” and “Why don’t we talk about this more.”

“The campaign is all about seeing signs of what can lead to worse things, and signs of people who might need help,” she shares.

And Williams has personal ties to the cause.

Credit: Roy Rochlin/Getty

“I have a really, really close friend of mine who was involved in a domestic abuse situation and it was really difficult, because she couldn’t see the signs — and the were signs there, and we all tried to tell her, we all tried to help her, but she just had to come to it on her own and see it on her own,” explains the 37-year-old champion tennis player. She continues, “We had to let her know we were there, and partners and people that are doing this want to make you feel so alone and that no one loves you and no one cares about you.”

Says Williams, “It means even more to me because now she’s broken free of that relationship and she wants to do a lot to talk about this.”

The athlete acknowledges that she has a platform “that most people don’t” — which is why she’s using it to spark change.

“When things hit so close to home, I think it’s so important to use your platform and your opportunities to not only have fun with your platform but also talk about things that are important to you. And this is important to me.”

The Allstate Foundation Purple Purse helps to empower victims to break free of abuse, and has invested more than $66 million since 2005 to help survivors.

“Not all abuse is visible. Unlike the marks and bruises of physical violence, the signs of financial abuse can be difficult to see — even for victims experiencing it,” Ellen Lisak, senior program officer for Allstate Purple Purse, tells PEOPLE. “They can range from an abuser giving their victim an unrealistic allowance for living expenses to preventing them from working to refusing to pay bills or maxing out credit cards in their name.”

Lisak says that the cornerstone of the program is their free Moving Ahead Curriculum — which she describes “a comprehensive educational resource designed to help survivors become financially self-sufficient.” Over 11,000 nonprofit advocates have been trained to teach the curriculum to survivors across the United States.

Williams — who will play in the U.S. Open this week — hopes that the new campaign and PSA will help “encourage the public to learn the signs of financial abuse and start conversations to help millions who are trapped.”

If you suspect domestic violence, call the National Domestic Violence Hotline at 1-800-799-7233, or go to thehotline.org. All calls are toll-free and confidential. The hotline is available 24/7 in more than 170 languages.