Olly Murs is terrified of swimming because of his 'penis eating' fish phobia.
The 38-year-old star has admitted he's "scared" after hearing a story about a man who "went for a wee" in the sea only to find a fish "inside of his urethra".
Appearing on Alan Carr's 'Life A Beach' podcast, he said: "I'm scared of the sea. I'm scared of the water.
"It's only because I heard a story once about a guy who went into the sea at night time. He went for a wee and he felt a shock, but didn't know what it was.
"A couple of weeks later he had to go to the doctor because he had a swelling situation downstairs - by the way, this isn't me, don't think this is my story.
"Anyway, he's found a fish had lodged itself inside of his urethra."
The animal he's referring to is the candiru - often known as the 'penis fish' - which is a tiny parasitic catfish which is thought to swim into body openings of unprotected swimmers.
The 'Dance With Me Tonight' hitmaker urged people to take care if they "go skinny-dipping", while he's taken an important lesson from the cautionary tale.
He added: "When you're in the water, if you urinate in the sea they get attracted to the heat.
"Just be careful if you go skinny-dipping. If you feel a little pinch you know what's happening.
"I'll never, ever wee in the sea ever again."
Meanwhle, Olly recently proposed to personal trainer and bodybuilder Amelia Tank after three years together, and he admitted it didn't go as smoothly as he hoped.
Last month, he said: "I did get down on one knee — the only slightly embarrassing issue was she had to help me up after my recent knee operation.
"Fortunately she said yes all the same, we couldn’t be happier.”
Olly also revealed he is hoping to tie the knot with his fiancee next summer.
He said: "We want to get married next summer. That is tricky because we got engaged in June so only have a year to figure it out.
"But it was the right time, it was perfect. Everything about me and Amelia is perfect so it was really just a question of how can we make it even better?”