D.J. Caruso dreams about making movies.

The 'I Am Number Four' director admits his heavy workload means even his sleep is affected by his job and he once thought he had shot a scene when he had in fact only dreamt it.

He told BANG Showbiz: "I dream constantly that I am shooting. In fact, one day, I was convinced that I shot a scene already, but it turned out it was only in my dream. It is 24/7."

When he is working on a movie, he likes to think of it like a game of sport and "attacks" a film like he would a match.

He added: "I feel like playing sports and competing was a great way to prepare to become a filmmaker. I attack each shoot day like a game that I must win.

"The actors trained for three months in order to fight and do the stunts required. So they too have are like athletes who must perform well on a given day. They train hard and the day they shoot the stunt they are like athletes."

The DVD of 'I Am Number Four' is released on June 20.