New Delhi, Jan 26 : Despite of starring in a string of successful films in his career, Tom Cruise "can''t sleep" before he starts filming a movie.

The `Top Gun' actor still gets excited about starting a new film, even though he has been in the business for over 25 years.

"I can''t sleep the night before I start to shoot. I care about the work I do," he said.

And the actor has said that he was particularly keen to begin making new movie ''Valkyrie'' because he found the story so engaging, reports the China Daily.

"When I read the script I couldn''t wait to turn the pages to see what was going to happen next. Even though I knew the outcome, I got caught up in the piece. This is a film I felt was important," he said.

In the film, which tells the story about a plot to kill Adolf Hitler, the 46-year-old actor plays the role of Colonel Claus von Stauffenberg.

Cruise has claimed that he always tries to take on difficult roles but found his latest part particularly tough.

He said: "I''ve always taken on challenging roles. This was very challenging because it was a suspense thriller, and yet here we are dealing with actual events." (ANI)