Jennifer Aniston is frightened that age is catching up with her after she found a grey hair.

The former Friends star - who hits the big 4-0 on February 11 - says that she freaked out when she discovered a wiry grey hair lurking beneath her golden locks recently.

Jen told Ellen DeGeneres, "I have to say really, I feel better than I ever felt in my life.

"I did have a moment, though, over the weekend. My first like, 'Huh...I don't want to (turn 40)'.

"I found a really long grey hair and it kind of flipped me out. It's not my first but it's the fact that it was so long.

"I was like, 'Oh, how many others are there and what does that mean?' It actually brought me to tears slightly."

See Jen holding back the years at the Hollywood premiere of He's Just Not That Into You