Veteran actress Diane Keaton has ruled out undergoing plastic surgery to restore her youthful looks, because she is convinced she's too old.

The Annie Hall star, 68, reveals she used to contemplate going under the knife to hide the signs of ageing, but now she believes the opportunity has passed her by.

She tells, "Looking in the mirror gets worse and worse - it's just hopeless! I should extend this, pull it all up... But I think it's too late.

"When I grew up, (plastic surgery) was the thing you would never do. That was horrible - you weren't authentic. Now I don't believe that for a second, but there's a point where you can't do it anymore because you become, like, a freak. People do the face-lift or the filler, and if you're too old you need to do both and you've created a new face! I haven't done anything.

"Luckily they help you out in the movies. A little airbrush, lighting."