She's such an icon, in fact, that Watson will be taking over the MTV Twitter account on March 26 to give you an exclusive look at the red carpet premiere of the film, from getting ready, to chatting with fans and beyond.
For the biblical fantasy epic, though, Watson took a different tact.
"[I was] a bit greasy, didn't shower too much," Watson joked when MTV News asked her about her "Noah" look, in Los Angeles.
When she came to set for the epic fantasy shoot, she was sporting a hairstyle that wasn't exactly period appropriate for the character of Ila.
"I actually had a bob at the time, and obviously that's not going to work for a biblical movie," Watson said. "So we had to figure out how we were going to adapt that."
In the film, Watson plays the wife of Noah's (Russell Crowe) firstborn son, Shem (Douglas Booth), who has to survive not only a supernatural deluge, but also battles against armor-clad warriors and the wrath of the unseen Creator.
Watson worked with "American Hustle" and "Watchmen" costume designer Michael Wilkinson, alongside the film's makeup department, going through multiple hairpieces to get the bob to work. But sadly, Watson's natural haircut wasn't meant to make it to film.
"You could see that it didn't look very real because I had short hair," Watson continued. "My hair and makeup artist was like, 'Why don't we just give you dreads?' "
We don't know whether Watson's dreads will inspire a style revolution, but you can check them out for yourself when "Noah" hits theaters on March 28.