I know someone who looks like her. I've know her for years, she's in her 50's, never had a bit of work done, doesn't even wear make up. She has naturally curly hair and is very low maintenance.
I swear she does not look a day over 32/33. She has a light-up-the-room smile, is absolutely beautiful and her lovely personality shines through as well.
I just think that some people just have a radiance that most of us don't! Nigella might have had a bit of work done, but she's stunning, no doubt about it.