The 48-year-old producer Michael De Luca said the chemistry has been "hot" as they "genuinely enjoy each other", reported E! Online.
"It's hot. I think we are a little more than halfway through but it's going really good. I'm excited!" the producer said.
"The chemistry is there, they genuinely like each other. They're enjoying the story, the story is so powerful," he added.
24-year-old Dakota Johnson will play the role of Anastasia Steele from the adaptation of EL James novel while 31-year-old 'X Men' star Jamie Dornan is in the lead character of Grey.
The steamy scenes are going to be much tamer in the movie.
"It's less racy than the book. They felt it would be too much, so they have dialed those scenes back," a source said.
