Simon Cowell is allergic to wool.
The 48-year-old music mogul explained his aversion to lambs' wool means he has to spend a fortune stocking up on the very best cashmere jumpers.
Simon said: "I've got an allergy to lambs' wool. My secret is that I buy rather expensive cashmere.
"In fact, if I find a cashmere jumper I can wear without getting itchy, I don't just buy one, I buy five in five different colours."
Simon's extravagant shopping habits also extend to other areas of his wardrobe.
He added to Britain's Daily Mail newspaper: "I've found buying five cashmere jumpers at a time has made life much easier, so when I go shopping I buy five of everything - five pairs of the same jeans or five pairs of the same shoes."
To ensure he always looks his best in his luxurious clothes, the 'X Factor' judge is careful not to indulge in calorific treats.
In fact, he is so conscious about staying in shape he hasn't eaten a biscuit since he turned 40.
He said: "Once you get to 40, you really have to be careful about what you eat. Biscuits, cakes and chocolate are definitely off the menu."