Forget the facelift and push aside the anti-ageing creams - all you need to do is smile.
A study has found that the simple act of looking happy takes years off a person's age.
The German researchers say that it's probably because we consider people who are cheerful as being attractive in other ways, including being younger than they actually are.
Temporary wrinkles created by grinning also makes it more tricky to judge a person's age and so may lead those doing the guessing to err on the side of caution.
Manuel Voelkle, of the Max Planck Institute in Berlin, asked more than 150 men and women of different ages to judge the ages of the faces in more than 1000 photographs.