The genius reason why Cristiano Ronaldo wears nail polish with Mike Tyson also using same method

Fans have noticed the colour of Cristiano Ronaldo's toenails in a new social media post, but there is a very good reason for the polish.

On Thursday, the five-time Ballon d'Or winner shared a picture of him and 13-year-old son Cristiano Jr showing off their physiques after a gym session.

The post on Instagram accrued more than 15 million likes but not for the first time, plenty of people picked up on Ronaldo having nail polish on his toenails.

It happened previously when he shared a snap of him recovering in the sauna and there were comments such as, "Why bro got black toe nails?" and "Is no one going to talk about the black painted nails?".

But Ronaldo does not paint his toenails black for aesthetics as there is a genuine purpose for him doing so.

Image: Instagram/@Cristiano

As per German outlet BILD, the 39-year-old paints his nails to prevent fungi and bacteria as an athlete, he spends a lot of time in sweaty shoes and boots.

The polish effectively creates a protective layer and hardens the toenails, stopping them from being cracked.

It's common in sports, particularly with track athletes and boxing and MMA fighters.

Heavyweight legend Mike Tyson is believed to have painted his nails in the peak of his boxing career.

And former UFC middleweight champion Israel Adesanya is also onboard.

Only last month Ronaldo was spotted wearing a black ring despite not being married to other half Georgina Rodriguez.

Image: Getty

The ring is a smart fitness ring from Finnish firm called 'Oura Health' and costs around £236.

It tracks how much sleep Ronaldo is getting, as well as his heart rate, body temperature and movement among other things.

Ronaldo is the definition of a fitness freak, following a strict routine which includes napping five times a day.

His pattern appears to be working though, as he is still going strong as he approaches 40.