Charlize Theron has revealed how she was “hit pretty hard with depression” after gaining 50 lbs in weight through eating lots of junk food for a new film role.

The 42 year old actress’s latest movie part is one of the leads in Tully, where she plays an overwhelmed and stressed mother of three, a part for which she had to gain over three and a half stones. To this end, Theron had to stick to a diet of eating unhealthy, high-fat food – even forcing herself to wake up in the night to eat.

She told Entertainment Tonight on Wednesday (April 18th): “I would literally wake up at two in the morning and I’d have a cup of cold macaroni and cheese just next to me. I would wake up and I would just eat it… I would just, like, shove it in my throat. It’s hard to maintain that weight.”

Charlize TheronCharlize Theron had to put on 50lbs for 'Tully' role

Actually being allowed to eat loads of junk food as part of your job sounds like heaven to most of us, but for Theron it was simply a means to an end for her method acting as she sought to get inside her character’s mind.

“I just I wanted to feel what this woman felt, and I think that was a way for me to get closer to her and get into that mindset,” she explained. “You know, it was a huge surprise to me.”

More: Charlize Theron reveals she co-parents her kids with her mom

Furthermore, changing her diet so drastically didn’t hold much novelty value and, soon, she began to feel low as a result of the constant sugar rushes and crashes, and found it much harder to shift the weight this time around compared to her Oscar-winning role in Monster 15 years ago.

“I got hit in the face pretty hard with depression. Yeah, for the first time in my life I was eating so much processed foods and I drank way too much sugar. I was not that fun to be around on this film.”

Tully sees Theron play Marlo, an exhausted mum of three young kids (including a newborn baby) who forms a bond with a nanny named Tully who comes into their lives. The film premiered at the recent Sundance Film Festival, and is given a wider cinematic release on May 4th.

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