Dakota Johnson has started a juicing diet to help her get in tip-top shape for the role of Anastasia Steele in the movie "Fifty Shades of Grey." Because of the highly erotic natural of E.L. James' novel (which the movie is based off of), it's expected there will be a lot of nudity.

Sources revealed to E! News that Johnson and director Sam Taylor-Johnson have been consuming organic juices while on set. The 21-year-old actress was recently photographed drinking the Juice Box's Tumeric Tonic, an organic beverage that consists of turmeric, lemon, ginger and organic raw wildflower honey.

The juices will not only help the actress look amazing in the nude but is said to also give her tons of energy so she can get through the long filming days.

"They are sometimes starting as early as 6:30 a.m., and there are long hours," a source told E! "The juices help them feel great and maintain a high nutritional intake. They energize you and you don't get the same crash with sugar or coffee. It is more a sustainable energy level."

Johnson is said to be ordering her organic drinks from The Juice Box, a Vancouver-based company, where the movie is currently filming.

"They order the organic cold-press juices," the source said. "They love them. They have a standing order for them. [They] are not doing a cleanse and are basically drinking a couple each day."

The "Ben and Kate" star is also working out and was spotted several times in workout gear as she left the gym. It's good to know that the actress is fully committed to the movie. She recently spoke about playing the shy college student to Entertainment Weekly.

"I just really understand it," she said. "I think it's an incredible love story and that's why it's affected so many people. [Author E.L. James] did a really good job of explaining how that just can happen sometimes and you have this chemical pull to someone. Adding in the sex makes it perfect. Sometimes you feel a little bit naughty and that's okay."

"Fifty Shades of Grey" is scheduled to hit theaters Feb. 13, 2015.