Charlize Theron has opened up to Ellen DeGeneres about her 50 pound (22 kg) weight gain for her new movie Tully, saying she "dealt with depression for the first time".
The Monster actress told DeGeneres she ate endless bags of potato chips to put on weight for the role as a mother struggling with modern life.
The 42-year-old admitted she even stored bags of potato chips, "my drug of choice", in the bathroom.
"I ate them everywhere. I had a bag in my car, a bag in my bathroom, a bag in the kitchen, a bag in the couch, a bag in my trailer - everywhere I went, there was a bag."
Theron said the hardest part was how much the processed diet affected her mental health. "I dealt with depression for the first time," she revealed.
"What they say about 'what you eat is who you are' is so true, because I ate like a person who just didn't move and I felt like that," she continued. "I was lethargic and tired all the time, and that was a hard thing to break. Because it's more mental than it is almost physical."
She also said losing the weight after filming was "brutal".
"In retrospect the film deals with what parenthood looks like today. It's so insane to me that we share so much information, but for some reason when it comes to parenting there's still so much stigma and stuff we don't talk about a lot of stuff.
"It's strange mothers do this every day: they get pregnant and they gain all this weight and if they don't lose it in a year and a half they get judged," says the mother, who welcomed her son Jackson, 6, and August, 3, via adoption.
"I felt like I had to do it for the film".