Tennis star Serena Williams stuns in the 2017 Sports Illustrated Swimsuit Issue. In a recent interview, she explained that this was the first time she wore a thong bikini. She added: The thong is perfect, it really made me feel comfortable. I'm officially a thong girl now!" Williams added that she definitely wanted to send a message with her photos. Although she isn't a size two, Williams explained that she can still look and feel beautiful.