A study has shown that a beard could make a man age up to ten years, a moustache can add five years, a goatee could make a man age up to four years and stubble could add three years.

A panel of 300 people was shown pictures of various celebrities who regularly change their facial hair. They were asked to guess how old the stars looked when they were clean-shaven, had stubble, a moustache, a beard or a heavy beard.

Celebrities such as David Beckham, George Clooney, Roy Keane, Brad Pitt, Robert Pattinson and Ben Affleck were shown to the panel.

Keane, 43, was adjudged to look 50 with his bushy beard.  When clean-shaven, he was said to look just 40 – three years younger than his real age.

The panel aged David Beckham at 35, four years younger than his real age when he was clean-shaved, however they said that his current facial hair is making him to look 40.

Brad Pitt however defied the beard thing as panel aged the 50-year-old actor at 49 with his goatee and just 45 when clean-shaven.

The panel judged Robert Pattison to be 28 (which is his actual age) with his beards on and 25 when clean-shaven.

The research was carried out by Crown Clinic in Manchester, a leading Britain’s hair transplant centre.