Domestic abuse affects one in four women and one in six men in their lifetimes, and now Serena Williams has come together with Purple Purse by the Allstate Foundation to create a powerful video highlighting the invisible signs of domestic abuse - and financial abuse in particular.

In the video, Williams is seen getting ready for a tennis match.

“If I limped on to the court, you’d notice,” the celebrated tennis player says. “If I had black eyes and broken bones, you’d notice.

“If I had marks on my arms and fear in my voice, you’d notice. It’d be easy to see that I need help, to know something was wrong. But what about the abuse you can’t see?”

The video goes on to explain that “financial abuse is an invisible weapon” and that “it happens in 99 per cent of domestic violence cases, and it’s why many victims can’t just leave.”

Williams is an ambassador for the charity behind the video, Purple Purse by the Allstate Foundation, which campaigns to raise awareness of domestic abuse.

Financial abuse (also known as economic abuse) is a form of coercive control.

It can take various forms, however some of the most common ones are controlling someone’s access to bank accounts, placing restrictions on spending and only allowing a partner a strict allowance.

Serena Williams vs Naomi Osaka: Story of the US Open women's final Show all 8 1 /8 Serena Williams vs Naomi Osaka: Story of the US Open women's final Serena Williams vs Naomi Osaka: Story of the US Open women's final Serena gets headed Serena Williams was aiming for her seventh US Open title against Naomi Osaka, but things did not go her way. Reuters / USA TODAY Sports Serena Williams vs Naomi Osaka: Story of the US Open women's final Naomi Osaka wins first set The 20-year-old from Japan won the first set 6-2, but there was drama ahead Getty Serena Williams vs Naomi Osaka: Story of the US Open women's final First the coach Williams was penalised for what the umpire deemed to be coaching from the sidelines by Partrick Mouratoglou. She disagreed and the war with the official began by Williams saying she was not a cheat. “I don’t cheat to win,” Williams told Ramos after he had issued the code violation. “I’d rather lose.” Getty Serena Williams vs Naomi Osaka: Story of the US Open women's final Then the racket Williams took her anger out on her racket after dropping a serve, the penalty was a point deduction. “You owe me an apology. I have never cheated in my life," she told the umpire. "I have a daughter and I stand for what is right.” USA TODAY Sports Serena Williams vs Naomi Osaka: Story of the US Open women's final And finally, the tournament referee A furious Williams received a third code violation for verbal abuse and demanded to see the tournament referee, Brian Early. An increasingly upset Williams told Earley that male players say far worse without receiving similar punishment and said she was being penalised “because I’m a woman”. AP Serena Williams vs Naomi Osaka: Story of the US Open women's final Naomi Osaka wins 6-2 6-4 Naomi Osaka won her first Grand Slam, but the match will be remembered for a completely different reason. Getty Serena Williams vs Naomi Osaka: Story of the US Open women's final Williams priases Osaka Williams was hesitant to do her on-court interview but praised Osaka's performance. "I don't wanna be rude or interrupt or do questions. I wanna say she played well, it's her first Grand Slam. I know the guys were rooting and I was rooting too." Getty Serena Williams vs Naomi Osaka: Story of the US Open women's final Williams calls for fairness "But I've seen other men call other umpires several things. I'm here fighting for women's rights and for women's equality and for all kinds of stuff. For me to say 'thief' and for him to take a game, it made me feel like it was a sexist remark. He's never taken a game from a man because they said 'thief'. It blows my mind," she said. "I just feel like the fact that I have to go through this is just an example for the next person that has emotions, and that wants to express themselves, and wants to be a strong woman. Getty

“Financial abuse involves a perpetrator using or misusing money which limits and controls their partner’s current and future actions and their freedom of choice,” Women’s Aid explains.

“It can include using credit cards without permission, putting contractual obligations in their partner’s name, and gambling with family assets.”

Financial abuse typically occurs alongside other forms of domestic abuse, with the victims being made to feel dependent on their abusive partner.

However, as Williams points out in the video, there are often no obvious signs to the outside world that this may be happening.

“Sadly the vast majority of survivors experience financial abuse at some point,” Women’s Aid says.

This is something Williams is hoping to change.

“I’m proud to speak up for women who can’t use their voices, and let them know we’re working to end the cycle of abuse,” she said in a statement.

“I hope that after viewing the video, people will be more aware of the hidden signs of financial abuse and they’ll understand the need to help those who’ve been burdened by it.”