Emma Watson has revealed she needed to put herself back together after filming Noah as it left her 'physically and emotionally exhausted'.

The 23-year-old star told E! News, "You see the movie and you go, 'Wow, we are entrusted with this beautiful world', and it kind of makes you want to make more of an effort and give back instead of take.

"I was so physically and emotionally exhausted by just the process of making the film. I just didn't leave my apartment for a few weeks [afterwards], walked around in my pyjamas for a few days in a row. I just needed some time to sort of put myself back together a bit."

Noah is set for release on April 4.

Emma Watson

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Jennifer Connolly

Paul Bettany and Russell Crowe