As the weather cools down, the tennis court heats up at Billie Jean King National Tennis Center.
That's right: The 2017 U.S. Open kicked off in late August, and the stars poured into New York to watch some of the best names in tennis face off in Arthur Ashe stadium.
The festivities officially kicked off on Monday, Aug. 28, as celebrities flocked to the 17th annual USTA Foundation Opening Night Gala at the USTA Billie Jean King National Tennis Center in Queens. Shania Twain (who also happened to be celebrating her 52nd birthday) performed for an eclectic group, including Pharrell Williams, Luke Bryan, and Katie Couric.
Since the tournament started, celebs from Victoria Beckham and her son Romeo to Leonardo DiCaprio have been spotted in the stands. But perhaps the cutest little tennis fan we've seen yet is Olivia Wilde and Jason Sudeikis's 3-year-old son Otis, who took in the action at Arthur Ashe stadium while mom and dad chatted with James Franco.
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Scroll down for all the stars at the 2017 U.S. Open.