Charlize Theron thought she was “dying” when she was tasked with putting on weight for a movie role

She said: “It was brutal in every sense. This time around, I really felt it in my health. The sugar put me in a massive depression. I was sick. I couldn’t lose the weight. I called my doctor and I said, ‘I think I’m dying!’ And he’s like, ‘No, you’re 41. Calm down.’”

And it wasn’t just her weight that the blonde beauty struggled with on set, as she also revealed she ended up cracking her teeth from clenching her jaw too hard whilst learning some of the tough moves she’d have to do in the feature.

She added to Variety magazine: “It happened the first month of training. I had severe tooth pain, which I never had in my entire life. [The dentist had] to cut one of the teeth out and root canals. It was tough. You want to be in your best fighting shape, and it’s hard. I had the removal and I had to put a donor bone in there to heal until I came back, and then I had another surgery to put a metal screw in there.”

Meanwhile, the 'Mad Max: Fury Road' star recently revealed her gruelling fitness regime, in which she undergoes two 90 minute power yoga sessions and attends spin classes "three to four times" per week to help her stay in shape.

She said: "[I work out] three to four times a week."

However, the star doesn't find exercising a "chore" because she has found disciplines she enjoys.

She said: "I've always believed if you find something you love, exercise won't be a chore.

"If you do exercise you enjoy you're keeping yourself fit without even realising it."