News Serena Williams Totally Surprised 2 Fans on a Tennis Court When She Showed Up to Play By Raphael Chestang 3:46 PM PST, February 27, 2017 Getty Images Two men playing tennis on a court in San Francisco, California, got the surprise of a lifetime when Serena Williams (the greatest player of all time!) wandered up and asked to join in on the fun.While out for a stroll with her fiancé, Alexis Ohanian, and her dog, Chip, on Sunday, Williams caught the sudden urge to pick up a racket when she spotted the pair playing out a match.Serena played tennis in boots with these 2 guys she saw on a court while she was out on a walk last night. IMAGINE. pic.twitter.com/kWXrTE73M9— Alysha Tsuji (@AlyshaTsuji) February 27, 2017"I'm thinking about asking these guys if I can hit with them, just to see their reaction," Williams said in a SnapChat story that documented the entire exchange.At first, Williams wasn't sure if the men would recognize her, but the fellas almost immediately proved her wrong.WATCH: Serena Williams Strips Down to Lingerie and Dances Like No One's Watching in New Ad"Is this for real?" one of them asked as Williams approached."Yes, please!" the other said at the prospect of playing with the winner of 23 Major singles titles.Despite wearing boots and not tennis shoes, Williams jumped in with the duo for a quick workout.WATCH: Serena Williams Gives Fans the First Look at Her Engagement Ring From Alexis Ohanian"The moral of the story is, you never know when I'm coming to a tennis court near you," Williams said.Serena Williams Defeats Sister Venus to Win Australian Open: 'What a Night For Our Family'