In a joint interview with ESPN.com, the Williams sisters discuss how much their relationship has changed over the years. At 33, Venus is one year older than Serena.

"I think a big difference is that Serena's grown up a lot and has become more and more of her own person," said Venus. "She is the youngest of five, and when you're the youngest of five you want to be like all the oldest ones. Especially in the last two years, she's been able to become her own person and really be her own self. I'm really proud of her."

Serena, who with 17 Grand Slam singles titles owns 10 more than Venus, laughed that perhaps she put too much emphasis on being like the older girls early on.

"I never wanted anything else but to be Venus, which I see now is kind of pathetic," said Serena. "When I didn't copy Venus, I copied my other sister Lyn. I'm just a copycat….We didn't fight—we weren't allowed to fight—that was a rule in the house. But I remember the only thing I didn't like was my body image. We always used to be the same, same, same, same, and then I changed and she was always the same. It's not something I didn't like about her, but that I was definitely envious of as a teenager."

Serena added that she’s happy with how she's turned out.

"Oh yes, I'm happy now. Oh God, curvy is in. I'm in style now," she said. "She's out of style, and I'm in style."