Charlize Theron reportedly gained 50 pounds by eating mac and cheese at night

The actress made a major change for an upcoming role, but it wasn't easy for her to do it.

In the run-up to her part as an exhausted mother on Tully, Charlize Theron had to pack on the weight, and she ended up gaining over 50 pounds.

As reported by Page Six, Theron wanted to be able to feel like her character, and get into her particular mindset.

But Theron was surprised by what packing on the pounds did to her not just physically, but also mentally and emotionally.

“It was a huge surprise to me. I got hit in the face pretty hard with depression. 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,” she said.

The 42-year-old Oscar winning actress was eating around the clock in an effort to keep the weight on, admitting she was eating In-N-Out for breakfast. She also confessed that she needed to set alarms in the middle of the night to eat.

“I would literally wake up at 2 in the morning and I’d have a cup of cold macaroni and cheese just next to me,” she said.

She would force herself to eat it, regardless of whether she wanted it or not, shoving it down her throat in great forkfuls. For Theron, it was hard to maintain the weight.

Her weight gain was so shocking to her children, aged 6 and 2, that they both thought that she was actually pregnant again.

Once they were done filming, Theron was left with the daunting task of losing all that excess weight. It ended up taking the actress over 18 months to drop the pounds again.

“I was worried. I was like, this is taking a really long time,” she said. “Because on ‘Monster,’ I just didn’t snack for five days and I was fine."

But her age was a contributing factor to why it took her so long to lose the weight, and her doctor had to remind her that she was no longer 27.