Imagine playing a game of tennis with a mate when someone offers to play the winner. Nothing unusual there, until you look up and see that the owner of the offer is none other than women's world No.1 - and contender for the the title of the sport's greatest ever player - Serena Williams.
Well that is what happened when, fresh from winning a record 23rd grand slam at the Australian Open, Williams, out walking her dog, Chip, decides to have a bit of fun.
"Just having a stroll at night and I'm thinking about asking these guys if I can have a hit just to see their reaction," she says in the video that she posted to social media.
Her scheme is blown when the men recognise her as she approaches the court. "I think I heard them say my name already. Dammit," she says.
But they seem genuinely shocked by her appearance courtside, with one asking, "Oh my goodness, is this for real?".
Despite wearing far-from-regulation soft boots she takes to the court. Although the video does not actually show her playing, she can be heard telling one of the men, fluffs a forehand half way up the net to "don't get tight".
At the end, she says: "The moral of the story is, you'll never know when I will be coming to a tennis court near you".
Williams' video carries on a long list of escapades by sporting stars that, whether set up or not - some are publicity stunts, others are little more than viral commercials for sponsors - can often produce amusing results.
Serena Williams surprised two random fans and played tennis with them (via @AlyshaTsuji) pic.twitter.com/zZteLGQkxd
— Athlete Swag (@AthleteSwag) February 28, 2017