Tennis' greatest ever player Serena Williams was taking a leisurely stroll Sunday night around San Francisco with her fiancé, Reddit co-founder Alexis Ohanian, when something caught her attention: two guys playing tennis in Dolores Park.
At first she thought she might challenge them to a match anonymously, but being one of the greatest athletes alive, she was promptly recognised.
"Oh my goodness," one person on the court says. "Is this for real?"
Williams appeared to indeed to be for real, even though she didn't have her preferred tennis shoes — just a pair of furry boots. It seems she didn't play a full set, though; TMZ notes that the footwear may have held her back.
"Don't try this at home!" she told her Snapchat followers.
Watch the whole thing here, put together by USA Today's Alysha Tsuji: