Serena Williams will fight for equality until the "day she's in her grave"

She said: "The day I stop fighting for equality and for people that look like you and me will be the day I'm in my grave."

Serena suffered with post-natal depression following the birth of her daughter and opened up about her journey to help others.

She said: "Honestly, sometimes I think I still have to deal with it. I think people have to talk about it more because it's almost like the fourth trimester, it's part of the pregnancy. I remember one day, I couldn't find Olympia's bottle and I got so upset I started crying ... because I wanted to be perfect for her."

Serena almost died delivering her baby as she had to undergo an emergency caesarean section but experienced life-threatening complications, which resulted in surgery to prevent blood clots travelling to her lungs.

She explained: "For so many years, I defined myself in just one way: by success, by championships, by making history. And then, all of the sudden, my life changed forever. It wasn't part of any plan to have this happen, not while I was still on top. But two years ago, I met this man, almost out of nowhere. We fell in love, and then, this unthinkable surprise. I can't believe how much went wrong on my way to meeting her. I almost died. But now, she's the reason why this all means even more than it did before. Still, there's no escaping the fear. The fear that I might not come back as strong as I was. The fear that I can't be both the best mother and the best tennis player in the world. I guess my only choice is to live and find out."