Why Simon Cowell looks so different - and it's not what you think

Simon Cowell's fans were wowed by his eternally youthful appearance last week, but the secret to his fresh-faced look isn't what you'd imagine.

SEE: Simon Cowell unrecognisable in new video: fans all say the same thing

Fans wondered whether the Britain's Got Talent star had had cosmetic work done to achieve his glowing, youthful appearance, but a report by the Daily Mail suggests the reason for Simon's new look is actually down to his partner, Lauren Silverman.

WATCH: Simon Cowell's teeth: what has he had done?

"Lauren encouraged him to adopt better eating habits," Simon's friend, talent agent Jonathan Shalit, told the paper.

READ: Simon Cowell gushes with love about fiancée Lauren ahead of wedding

MORE: Simon Cowell injury recovery: how he's changed his life since accident

Simon's young son, Eric, is also motivation for the TV star, with Jonathan explaining: "Simon is a brilliant father who is keen to see his son grow up."

Simon spoke about Eric, eight, being his catalyst for change during a chat with TV host Ellen DeGeneres.

© Photo: Getty Images

Lauren Silverman is responsible for Simon Cowell's health overhaul

"I went to see this doctor in London and we did some tests, and then a month later he said 'you have the worst diet I've ever met from any patient'," The X Factor star previously told Ellen.

SEE: Simon Cowell's son, Eric, is his double in unbelievable new family photo

Simon, who is a regular smoker and drinker, recalled asking his doctor what he needed to give up in order to improve his health.

© Photo: Instagram

Simon's son Eric inspired him to become healthier

"It's pretty much all the things I loved that I can't now eat. So no dairy, no sugar, no bread, no gluten, no red meat," he said.

"I've gotta be honest with you, it was easier than I thought. And part of the reason I did it was because Eric is five this year so I realised that if I didn't sort myself out physically I wouldn't be able to catch up with him."

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