Austin Butler feared he was "dying" when he went temporarily blind

He told the new issue of Men's Health magazine: "It felt like the life was being sucked from my body.

"I suddenly felt a euphoric sensation, and I actually genuinely thought I was dying."

The Elvis star's sight slowly returned to normal and he went on to spend the entire day working on set, writing off the incident as a side effect of sleep deprivation.

Austin was convinced to put in the best performance, he had to be "tortured", and suffered several health issues as a result, including a pain in his foot for months after promoting Dune: Part Two and appendicitis-like pain that hospitalised him for a week after filming Elvis.

He said: "For a long time, I felt that it [acting] had to be a tortured process and I would come out the other side broken."

But mentors such as Laura Dern have helped him find balance between work and his health.

He said of the 58-year-old actress: "She's helping me more and more to see that you can come out the other side, and maybe bits of you have healed, and synthesized, and metabolised.

"It can be therapeutic, in a way.

"You don't have to destroy the light."

And the Once Upon a Time... In Hollywood actor has found ways to stop trying to erase himself in his performances.

He said: "Rather than just putting parts of yourself away and trying to pretend that they don't exist, it's like going into the gross bits of yourself - going into the bits that you don't want to look at - and finding a way of integrating that into the whole."

Austin famously poured so much into his Oscar-nominated portrayal of Elvis Presley, he needed to work with a dialect coach to get rid of The King's distinctive drawl afterwards, and he recalled feeling lost once filming ended.

He said: "And then it's done, after three years. And then it's like, Wait, what do I focus on now? What do I read about? What do I watch? What do I like? And also, I haven't talked to my friends. Who do I call?"