Cara Delevingne doesn't need sleep.

The 20-year-old beauty is one of the world's most in-demand models and insists she doesn't need a lot of rest as she has too much on her mind.

She said: ''I never really expected it to be like this. I always said, it can't get busier than it is now - and that was six months ago. This has been my first day off since fashion week.

''I don't seem to get tired, I just get more manic. Even as a child, I remember sleeping was never good for me. There's always so much going on in my head.''

Cara says she works better when she's under pressure although sometimes pushes herself too far.

She told Britain's Vogue magazine: ''I work under high anxiety. I leave everything until the last possible minute to stress myself out as much as possible. I do forget sometimes that I need to breathe slowly. I work myself up until I run into a wall.''