[VIDEO] Fifty Shades Darker Cast Rumors: Dakota Johnson keeps sexy shape not for Jamie Dornan, but for Cara DeLevingne?

There have been several rumors surrounding Fifty Shades Darker actors Dakota Johnson and Jamie Dornan. Several media outlets say the two are having an affair which has not died down since the success of their first film, Fifty Shades of Grey. However, it seems that model-turned-actress Cara Delavingne may not agree with that.

For Dakota Johnson to make sure that she keeps things steamy in the next installation of the Fifty Shades of Grey franchise, she needs to keep herself fit for the role. And although the actress manages to keep up with her on-screen romantic partner, Jamie Dornan, in terms of fitness. But off-screen, it seems another Hollywood actress keeps her motivated to work hard to stay fit.

According to Health Aim, rumors spreading claim that after St. Vincent dumped Cara Delevingne after moving on with Kristen Stewart, Johnson has been very supportive of the model. However, onlookers noticed that their closeness is getting more intimate to be only labeled as "friends".

The 27-year old actress even celebrated her birthday with Delevingne while chatting with Taylor Swift. However, though the two looks very compatible with each other, these rumors have not been confirmed by either camp.

Meanwhile, fans of the franchise have grown curious about how the actress manages to keep herself fit. Johnson has shared her secret for staying fit and fab which includes a healthy juice diet and an intense workout routine.

In a report by Foods4betterhealth, Johnson said that she maintains a strict juice diet which allows her to remain active. This also makes her look in tip top shape as well as looking blooming. The actress, who plays Anastasia Steele, reveals that she likes drinking raw fruit juices such as apple, lemon, ginger, orange, and cucumber.

As for her workout routine, the actress admitted that she wants to be confident while she reveals parts of her body on screen. Even though she was never a fan of exercise at first, she was amazed by how much it changed her. She said that it didn't only tone her body; it also helped relieve her stress, especially with her busy schedule.

Johnson also said that she likes Pilates. She works with a trainer Mari Winsor every day, five days a week for an hour each day. "Pilates is changing her body, relieving her stress. It's a private place for her to come and do the work," says Winsor.