'50 Shades of Grey' Movie Cast Rumors: Dakota Johnson Starving Herself With Juice Diet For ‘Fifty Shades’ Role, Or Just Being Healthy?

Playing the lead role of Anastasia Steele in the “Fifty Shades of Grey” movie adaptation means spending long, taxing days filming -- and being naked most of the time. That's why actress Dakota Johnson has reportedly implementing a strict juice diet on the set of the erotica film, due in theaters in February 2015.

According to multiple reports, Johnson has been strictly consuming juices on set, which raises the question: Is the actress trying to starve herself or just attempting to be more health-conscious? According to a report from Marie Claire, Johnson, 24, has taken on the juicing diet in an effort to boost her energy level on the set of the highly anticipated movie based on the erotica book.

“They are sometimes starting as early as 6:30 a.m., and there are long hours,” a source revealed to E! News, adding, “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 a more sustainable energy level.”

According to the insider, the film, which started production in Vancouver earlier this month, has been a strenuous experience for the former “Ben and Kate” sitcom star. “This will be a tough movie to film,” said the source.

Proof that Johnson is trying to live a healthier lifestyle was confirmed Tuesday when the “Fifty Shades” star was spotted leaving a gym in Vancouver. In photos obtained by Entertainmentwise, Johnson can be seen sporting classic gymwear, a heavy winter jacket, and a smile.

In September, Johnson signed on to star in “Fifty Shades of Grey,” the film based on the 2011 best-selling E.L. James adult novel of the same name. Johnson will star as lead Anastasia “Ana” Steele, a recent college graduate who falls for a charming, billionaire businessman named Christian Grey, played by TV actor Jamie Dornan.

On Dec. 1, the duo was spotted filming the first scene for the movie in the GasTown District of Vancouver. Fans speculated that the shoot was a reenactment of the “coffee date” scene from the popular trilogy series. The fictional lovers were last photographed in Vancouver late last week shooting their first on-screen kiss.