Shia LaBeouf repeatedly slashed his own face with a knife while filming 'Fury'.

The 28-year-old actor completely immersed himself in a role as a tank's gunner in the wartime drama and stunned his co-stars with the lengths he would go to in order to make his portrayal seem authentic.

Co-star Logan Lerman said: ''We were in make-up and they were putting cuts on Shia and I said, 'Yeah, yeah, it looks good.' And Shia was like, 'No, it doesn't look real.'

''Then he walks out into the hallway and says, 'Hey man, wanna see something fun? Check this out...' and he takes out a knife and cuts his face. And for the whole movie he kept opening these cuts on his face. That's all real.''

And the 'Nymphomaniac' actor also insisted on having a dentist remove one of his teeth.

Logan added: ''I mean, he didn't do it himself, he did go to a dentist and asked them to pull his tooth out but yeah, what an odd request.''

Shia - who didn't wash during filming - learned to operate the tank to an expert level and insisted on staying in control of the vehicle even when he wasn't needed on set.

Logan told Britain's GQ magazine: ''He really spent every moment on that set. He's the guy operating the turret in every shot, even when you don't need to be in there as an actor. You know, you can have somebody else inside. But he was there, for every shot.''