Charlize Theron says she gained 50 pounds for 'Tully'

April 19 (UPI) -- Charlize Theron says she gained "close to 50 pounds" for her film Tully.

The 42-year-old actress recounted at the movie's press junket Tuesday in Los Angeles how she gained weight to play a mom-of-three in the new dramedy.

"I just 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," Theron explained.

"I got hit in the face pretty hard with depression," she said. "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."

Theron packed on the pounds over a three-and-a-half month period. She said gaining weight was initially fun but turned into a chore.

"The first three weeks are always fun because you're just like a kid in a candy store," the star said.

"Then after three weeks, it's not fun anymore," she added. "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."

Theron said she went through "hell" to lose the weight after filming ending. She previously said in an interview with Variety that the experience with Tully was "brutal" compared to transformations for roles in her 20s.

"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,'" the actress recalled.

Tully follows the friendship between a mom (Theron) and her nanny (Mackenzie Davis). Theron was all smiles Wednesday at the movie's premiere in Los Angeles.