Simon Cowell wears a wig, according to fellow 'X Factor' judge Louis Walsh.The Irish music mogul - who returned to the judging panel on the British TV talent show earlier this year after being fired - has noticed that 48-year-old Simon never seems to age, and is convinced he is getting help to stay looking youthful. He said: "I think Simon's had some surgery done this year. He looks so different from last year. He hasn't got a single wrinkle or grey hair. I reckon it's a wig - it never moves!"Louis admits sitting alongside Simon and the other two judges Sharon Osbourne and Danni Minogue has inspired him to go under the knife. He told New! magazine: "I'd definitely consider having surgery. Sharon and Danni have had so much done - nips, tucks, everything! But they look great."Both Sharon and Danni have undergone a variety of cosmetic procedures. Australian pop singer Danni has confessed to having Botox and is rumored to have had a nose job, breast implants and collagen injections. Sharon has previously admitted to spending over £300,000 (US $ 600 thousand) on plastic surgery,including liposuction, a tummy tuck, Botox, a boob job, a face lift and a butt lift.