He wrote: "I can't really swim. Today I took my first swim lesson since I was like five. My dad learned in his 60's so I feel like I'm ahead of schedule."
A fan then joked that he was lying on his song "All of me" because of the line: "My head's under water/But I'm breathing fine."
They quipped: "So what happened when your head was under water? Did you breathe fine? Was it all a lie?!"
John is not alone in not being able to swim.
Many celebrities have revealed over the years that they either can't swim at all or have a fear of water, including Will Smith, who only learned in 2016 and Zayn Malik said he had a fear of open water preventing him from hitting the pool.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)