Who knew Redfoo was such a tennis fan?

The LMFAO singer has been showing his fuzzy ball love at the U.S. Open, hanging out with the stars, promoting his tennis fashion line and coaching junior Ayaka Okuna.

Redfoo, who played the junior tennis circuit growing up in Southern California, showed up in his trademark day-glo at top-seeded Victoria Azarenka’s press conference on Sunday.

Redfoo’s clothing line has signed on as the title sponsor for a $50,000 USTA women’s event next month in Las Vegas, appropriately named the Party Rock Open.