The 49-year-old admits the lonely sessions took a serious toll on her mental health, reports femalefirst.co.uk.
Director Alfonso Cuaron had to keep a close eye on her to ensure she didn't lose her cool and he used her son, Louis, to cheer her up whenever he felt she needed a boost.
"I was depressed, I was angry, I would get so sad because it was a black room, no human contact, they took away sound... 'What they did was, Alfonso could see, because he had cameras always on my face, he would be like, 'She's cracking, she's cracking, go get the kid'," Bullock said on a talk show.
"They'd created this whole wonderland just outside for Louis (to keep him occupied during filming), so they brought him in," she added.
--IANS (Posted on 14-10-2013)