Tom Cruise has revealed he works "seven days a week" to make sure he's always ready for his next film.

The 64-year-old blockbuster star, who is famous for doing his own stunts for franchises like Top Gun and Mission: Impossible, has revealed his strong work ethic starts a long time before he arrives on set.

He told Empire magazine: "I work seven days a week. I'm constantly studying and training on different things that I'm preparing for in the future...

"The thing I really try to focus on is how to prepare. Prep, prep, prep, prep, prep for everything."

For his new movie Digger, which is helmed by Alejandro G. Iñárritu, Tom has been physically transformed into an ageing wealthy oil tycoon, Digger Rockwell.

The actor admitted it was a gruelling process, and he even "slept at the lot" more than once during filming.

He recalled: "The first time I put the makeup on, it was six hours.

"And you have to understand, the makeup is here [pointing to his head] and heat comes out of your skull.

"I have my energy resources, in terms of what it's going to take to get that performance.

"I started doing the math. It was 19-hour days, basically. There were times I actually slept at the lot, in a trailer, overnight."

Tom put his mind to figuring out a way to streamline the process without making any compromises on the "quality" of the production.

He said: "I had boards put up, and I said, 'Look, by the time we finish this film, you're going to do the full makeup in under an hour'.

"'We're not going to sacrifice quality because I never wanted to sacrifice quality'.

"At first they said, 'That's impossible', and I said, 'If you think it's impossible, you've already closed the door.' "

Tom previously compared the role to several of his previous screen performances, including his memorable turn as foul-mouthed studio executive Les Grossman in Tropic Thunder, another performance that relied heavily on prosthetics and exaggerated physicality.

Appearing last month at a press event at Warner Bros. in Burbank, California, he said: "When we're looking for characters, we're looking for humor, drama, certain constructs - how do we communicate this?"

Tom continued: "Whether it's Les Grossman or Interview With the Vampire, Collateral, or Risky Business, I'm always asking, 'How do I communicate this?'

"The physicality, the make-up, that is stuff that you find as you are learning how to communicate."