The singer picked a fan, identified only as Adam, for the prank and decided to surprise him while he was working out.
The London gym was filled with backing dancers pretending to be other customers, and they all sprung into action when Minogue walked into the running machine room singing her track Into The Blue.
Speaking before the stunt, Minogue said, "It's a great opportunity to give something back to one of my fans. Let him know face to face I appreciate everything you do. It's pretty hilarious Into The Blue - I've never performed it before and I am about to do it in a gym... I've got one of my biggest fans in there, Adam, apparently he listens to my music while working out, but what he doesn't know is he's about to get me for real."
Adam was visibly shocked when he noticed the pop star walking towards him and singing as hidden glitter canons exploded, and he then joined Minogue for a dance during the number.
At the end of the performance, he told the singer, "Oh my God! Thank you!"
The stunt was organized in association with a Mastercard campaign.