Since Harry Potter, Emma Watson has continued to have quite the career. Although she continues to enjoy lots of success, the opposite has also held true in certain moments. Like Emma Watson turning down a game-changing role in La La Land, or leaving the set of This Is The End, after she realized her role wasn't exactly what she had envisioned.

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Her role in Noah was significant for multiple reasons. It was her return to a big budget film since Harry Potter and in truth, the actress did not disappoint with her performance.

However, behind the scenes, things were made a little more complicated. We'll take a look at what went down behind the camera, and why the conditions were so tough to handle for the cast.

Emma Watson's Role In Noah Was Physically Demanding But She Had The Prep In Her From Harry Potter

Directed by Darren Aronofsky, Noah was a big hit, generating strong reviews, while bringing in more than $359 million at the box office.

However, the shoot wasn't exactly easy, lasting months. In addition, the conditions were extremely tough. Speaking alongside Reuters, Watson recalled some of the toughest parts of the process, which included working late hours, and stepping into cold water outdoors.

"I remember being on set and Darren was saying, “Okay, the water is going to be cold, we’re probably going to be here for a full day, try and conserve your energy between takes, like keep warm and make sure you eat properly. This is going to be physically very demanding.”

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Although Watson worried about the scene and the conditions, she gave herself a shot of courage, thinking about what she had gone through during the Harry Potter days.

"For a minute I felt very intimidated and then there’s something about having done those “Harry Potter” films and they were very physical. We did a lot of stuff in Scotland."

Watson continued, "It was freezing cold, filming at four in the morning, working crazy hours. It’s kind of comforting in a way to know that in some senses, nothing will be as hard as that again."

Given her past with the Harry Potter franchise, Watson was willing to take on just about anything. However, things would take a turn during a very late shoot.

Emma Watson Became Extremely Dehydrated And Drank A 3-Month Old Glass Of Water

Most of the scenes for Watson were shot between 4 AM and 7 AM... not ideal times, Watson herself admitted she struggles to function at those hours.

She tells The Guardian, "Because of the storm, Douglas [Booth] and I ended up shooting most of our scenes between 4am and 7am - and at that time I never function well,"

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Making matters worse, water bottles weren't easy to come by on-set, given that it was a pro-environment feel. This would lead to Watson struggling with dehydration.

"Because the film has a pro-environment message, Darren didn't want anyone drinking from plastic water bottles on set either. So that made things slightly harder."

Given that it was 5 AM and the actress was feeling desperate for water, she decided to drink and old glass of water that sat out for three months. This only made things worse.

"I was so tired one morning I picked up a mug from my trailer and drank some stagnant water that had been there for the duration – so three months. I was so ill."

Feeling tired and ill, Watson wanted to skip out on the day. However, she was encouraged to do otherwise...

Emma Watson Was Encouraged By Darren Aronofsky To Shoot The Scene Despite Feeling Ill

The following day, Watson deemed that she was unfit to take on the scene. However, the director Darren Aronofsky had a different plan, wanting to use her state as a form of motivation for the film.

Emma Watson recalls the director's reaction, thinking he was joking.

"I came in the next day and was like: 'Darren, I don't think I can do this, I'm really sick,'" she said. "He was like: 'Use it for the scene.' And I turned round to the bus and was like: 'Is he joking? He is joking right?' and there was deadly silence."

A tough film for Watson, who made her return to big budget films for the first time since Harry Potter ended. She had worked a string of indie films prior.