Elizabeth Hurley has the ''discipline'' to look good.

The 'Royals' actress - who turned 50 in June - has revealed she's had her ups and downs when it comes to looking after her figure and has had to be strict with herself in order to ''shape up'' at times.

She explained: ''I certainly look different when I'm in the country, when I haven't been through hair and makeup. On those days I certainly don't look glamorous at all. But it's been part of my life having to shape up. I go up and down in weight, like everybody, and I definitely go through stages of looking after myself better at some times than others, but it's very much been a part of my career to have to look after myself. I think having that discipline has helped quite a lot.''

The brunette beauty - who has 13-year-old son Damien with ex-boyfriend Steve Bing - is aware she can't escape ageing and joked that being half a century old feels ''hideous''.

She told News.com.au: ''It was a hideous birthday this year. It's not a secret that I'm 50!

''The lucky thing for me is that as well as being in movies and TV, I've been in the beauty business with Estee Lauder all that time. So I have been incredibly privileged. I have had the best advisers and products at my fingertips for a long time. But like everybody, everything changes.''