Jessica Chastain has thrown herself into work over the past three years because she became "depressed" during downtime between projects.

The Zero Dark Thirty actress has taken on back-to-back film shoots since she hit Hollywood stardom in 2011, and admits she embraced the heavy schedule because she struggled with her private life when she wasn't working, insisting time off felt "a little bit like grief".

She tells U.K. Harper's Bazaar magazine, "I started to feel really negative about myself, down on who I am, and then I realised it's because I've had so much time away from me that I don't really know what I like to do anymore. I'm out of it now, but there was this feeling of being sad or depressed... wanting to go to another project."

The actress explains that working helps her overcome crippling shyness, adding, "I don't know what I'd do if I didn't have this form of expression because it offers me a freedom I don't have in my personal life... It's a beautiful prison I've created for myself."

After three years of working, Chastain decided to take a break. She has not been on a film set in three months and has no plans to start a project for the rest of the year (14).