Scientists might have just unlocked the secret to youth - and it all lies in the genes of those with red hair.
A new study found that the gene responsible for red hair, called MC1R, could be responsible for making a person look older than their years.
Manfred Kayser, professor of forensic molecular biology at Erasmus Medical Centre in Rotterdam and lead author of the study, told The Guardian: "This is the first gene we have found for perceived age, and this single gene has an effect of two years.
"We know there are others out there. We are just at the beginning."
It is thought the research could eventually enable scientists to develop ways to slow down the ageing process.
Researchers at the Erasmus University Medical Centre in the Netherlands and Unilever asked a group of people to analyse the bare faces of almost 3,000 people and guess their age.
The group of people had also provided DNA samples for a separate study.
After looking through the DNA data of the study's participants, they found that variations in the MC1R gene were more common in those who looked older than their actual age.
The study was then repeated in a further two groups of people, based in both the Netherlands and the UK, and the results were the same - the MC1R gene was evident in those who looked old for their age.
The scientists also looked at how the gene might work, as it is also responsible for producing pale skin - and fair skin is often more susceptible to sun damage, which can speed up ageing.
However they deduced that the effect of the gene remained the same even after ruling out skin colour, wrinkles and sun exposure.
Professor Kayser said the findings could be used to help people age healthily.
He said: "By finding more genes involved in perceived age, we can better understand the relationship between how old you look and how healthy you are. It is a different approach to understanding healthy ageing."
The MC1R gene has been previously linked to UV-related skin damage, pigmentation, freckles, age spots and skin cancer.
The study was published in the journal Current Biology.