Sergei Polunin: At first I was scared to go to Moscow
Sergei Polunin is one of the greatest ballet dancers of his, or any, generation. He was born in Ukraine and, at the tender age of 19, became the Royal Ballet's youngest ever male principal. But two years later he walked out, earning himself the nickname "the bad boy of ballet".
The story of his turbulent life in ballet is the subject of a new documentary out on 10 March called "Dancer".
The Today programme went to speak to him and asked why things started to go wrong.