Has he had copious cosmetic surgery then? His fellow X Factor judge Louis Walsh thinks he might have had pectoral implants.
"No, absolutely not. I have not had cosmetic surgery," he sniggers.
Botox then? He sucks his (extraordinarily white) teeth.
"Yes, I've had Botox, but not in an obsessive way. Then again, every guy I know who works in the City has had it now."
And what about the hair? Louis thinks it might be a wig. Then again, Louis is a known troublemaker, and Simon did fire him once.
"No, it's all real. I've never dyed my hair, ever, and I wouldn't," he says emphatically, though his eyes twinkle rather furiously.