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Whether on the court or on a magazine cover, Serena Williams has never seemed shy about flaunting her curves.

But the world's No. 1 women's tennis player says it wasn't always so.

"I grew up with a lot of sisters-I was the youngest, and I was really thick," Williams, 31, told the August issue of DuJour magazine. "My sister Venus was so tall and slim, and just being in a society where a lot of people are really thin, it was hard. Especially as an athlete."

"No athlete has boobs like me," Williams added. "I had to learn how to embrace myself and embrace my curves. And that's something a lot of people can relate to."

Williams told the magazine she began feeling more "comfortable with myself" six or seven years ago.

"That's why I tell people that even at 25 or 26, it's O.K. if you're feeling uncomfortable with yourself," she said. "I was too. It's normal. I love who I am, and I encourage other people to love and embrace who they are. But it definitely wasn't easy-it took me a while."

How Serena Williams Prepared for U.S. Open

Nowadays, Williams is as confident in her body as she is in her tennis playing. The five-time Wimbledon champion won her opening match at Monday's U.S. Open against 2010 French Open champion Francesca Schiavone and breezed through the second round with a 6-3, 6-0 victory over Galina Voskoboeva of Kazakhstan earlier today.

When she's not on the court, she's happy designing clothes.

"When I was younger, I made clothes for my dolls. My mom taught me how to sew when I was 2 or 3, so I've been sewing for as long as I can remember," said the designer of two collections.

Just recently, Williams showed off her sewing skills.

"I had a photo shoot the other day after I won a tournament, and when I put the dress on, it ripped," she told DuJour. "So I asked someone for the sewing kit and I just sewed it up right there. Everyone couldn't believe it. You could never tell it was broken."