Christian Bale explains why he dropped to 8 stone and slept for two hours a night to play The Machinist

Warning: Contains images some may find unsettling and discussion of extreme weight loss.

Christian Bale has explained why he dropped to eight stone and slept for only two hours a night for his role in The Machinist.

Prepare for your jaw to drop when you see just how different the 49-year-old looks in the film's trailer:

Many actors go above and beyond for the sake of their roles, altering their appearance so as to accurately portray a character's physical appearance as best they can.

However, in the 2004 psychological thriller The Machinist, directed by Brad Anderson, Bale altered his appearance radically to play the role of Trevor Reznik - a machine tool tradesperson who has been struggling with severe insomnia for over a year, leading him to experience paranoia and delusions.

The actor has since revealed why he lost over four stone and whose decision it was for him to do so.

To help pass the time while losing the weight Bale explained how 'a lot of times' he would 'sit there with headphones in' but not actually listening to anything, 'pretending to listen' so he could 'hear everything that was going on' around him without others knowing.

"Also, at the time I was engaged in a very filthy habit of smoking. So, I was rolling my own cigarettes and sitting there puffing away," he told GQ.

Paramount Classics

The actor also took it upon himself to read 'numerous things' from Crime and Punishment to lighter reads.

Bale reflected: "The main point was that somehow losing all the physical weight put all the energy into my brain and so I only slept two hours a night and all I wanted to do was read. And so I would just sit and read endlessly and I found that I could read without stopping or moving or needing a distraction. I could just sit and read for 10 hours straight without moving a muscle."

While activities such as reading and pretending to listen to music helped Bale through the weight loss, why did he decide to drop four stone in the first place?

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Particularly as even director Brad Anderson was 'stunned' at just how much weight the actor ended up losing for the role.

Bale explained: "I'd come off the back of making some films I'd been less than satisfied with and just really wanted something where I could become immersed and obsessed with it."

However, Bale admitted losing so much weight so drastically wasn't the 'smart thing to do'.

"There was no money in it and it was like, Ooh bloody hell, I'm gonna lose my place or [where] I'm living,' and I was quite newly married and all that, so it wasn't the business smart thing to do," he reflected.

Although he noted he's 'never been smart in a business way'.

Ultimately, rather than losing the weight for anyone else or because he had been forced to drop over four stone, Bale did it because it was 'something [he] really wanted to challenge [himself]' to do and achieve.

Bale reflected: "Could I fulfil how I imagined the part Trevor should be played? [...] And test myself?"

If you've been affected by any of the issues in this article and would like to speak with someone in confidence, call the BEAT Eating Disorders helpline on 0808 801 0677. Helplines are open 365 days a year from 9am–8pm during the week, and 4pm–8pm on weekends and bank holidays. Alternatively, you can try the one-to-one webchat.