The Sun says Ronaldo had goofy front gnashers as a child. He sported a brace after joining the Red Devils from Sporting Lisbon in a £12.2million deal in 2003.
And the wing wizard, now paid £7.3million a year, has since had extensive surgery to give himself a perfect pearly white smile.
Asked about his popularity with girls, he replied: "I'm a bit vain, I admit. I've had a few cosmetic things done and like to change my hairstyle.
"It would be hypocritical of me to say I think I'm ugly. I feel good about myself and that's the most important thing."
Sources explained that the "cosmetic things" involved dental work and not plastic surgery.