Matt Damon's hair has gone prematurely grey with the stress of raising children.

The Bourne Identity star, 43, is father to four girls with his wife Luciana, including her daughter Alexia, from a previous marriage.

He is adamant bringing up kids is one of his proudest achievements, but admits it has taken a toll on his appearance and has prematurely aged him.

Damon tells the U.K.'s Channel 4 News, "I have grey hair. I've four kids now and man did my hair go grey quickly!"