Jessie J

My attitude goes back to my childhood. I used to audition for theatrical roles, and you can't stand out in a room full of ambitious eight-year-old girls by acting the wallflower. I realised then that I couldn't do things half-heartedly.

The thing about dancing - what it taught me all those years - is it gives you an amazing sense of discipline in forcing yourself to do things that you know are good for you but you don't really want to do.