Tennis great Serena Williams looked incredibly fit (naturally) as she made her way into "The Late Show With David Letterman" in New York City yesterday.

The 14-time Grand Slam champion, 30, wore a form fitted red dress that zipped up in the back. She paired the look with black and white stillettos.

It's been a great year for Serena. She won the women's singles and doubles titles at Wimbledon, and at the London Olympics she won the gold medal in singles after defeating Maria Sharapova. She and her sister Venus also won the gold medal in doubles. Next week she competes in the U.S. Open.

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