Since 2015, the ‘Fifty Shades’ franchise has been taking the world of entertainment into uncharted territory. Never has a film franchise dealt with erotica in such an explicit manner. And never have films like these been promoted into the mainstream market.

Like a number of successful film franchises in recent years, ‘Fifty Shades’ also started out as a series of books. The author responsible for creating Christian Grey and Anastasia Steele’s world goes by the pen name E.L. James. She is a former executive who ventured into fiction writing in 2009. In 2012, her ‘Fifty Shades’ trilogy became a bestseller. And in no time, Hollywood came calling.

Today the franchise stars Jamie Dornan as Christian and Dakota Johnson as Anastasia. And even if you’ve seen all three ‘Fifty Shades’ films, we’re willing to bet there are some behind-the-scene secrets you don’t know about yet:

15 Robert Pattinson Was E.L. James' First Choice For Christian Grey

Screenwriter Bret Easton Ellis once tweeted, “Talked to E.L. James at a party over the summer: her first choice for Christian was Rob Pattinson and Matt Bomer was never in the running.” He added, “E.L. James and I were at Rob Pattinson's house when she admitted that Rob was first choice for Christian. Ian Somerhalder never in running.”

14 The Real Reason That Charlie Hunnam Walked Away From The Film Was Script Conflict

The ‘Sons of Anarchy’ star passed some notes on to the “Fifty Shades” screenwriter, Kelly Marcel. According to The Hollywood Reporter, “The notes were well received, according to sources, but that only led to Hunnam seeking further script approval, which was denied.” Meanwhile, another source told the publication that Hunnam and the creative team were “butting heads.”

13 Dakota Johnson Had A Thong Glued To Her While Shooting Fifty Shades Freed

Johnson explained, “They're, like, basically if it were a nipple pastie, but underwear. But it's only sticky at the top, it's not sticky the whole way. It would also come off because the adhesive would wear out, so then they would super glue it to my body so that it wouldn't fall off.”

12 While Making The First Film, E.L. James Didn’t Allow Her Scripts To Be Polished Or Rewritten

A representative with ties to the ‘Fifty Shades’ project told The Hollywood Reporter, “She will not allow herself to be rewritten, even if it's 'and' or 'but.'” A source also told the publication that James “just didn't seem to grasp that in all adaptations, some things need to change. You can't just put the book on the screen.”

11 Dakota Johnson and Jamie Dornan Occasionally Drank Before Filming The Tough Scenes

Johnson revealed, “Most of [our preparation] is just really figuring out exactly how we're [sic] going to accomplish the scene beforehand—so that there's not a lot of waiting around while we're both vulnerable. But, if something is very, very difficult, it's sometimes necessary to have a shot of something strong beforehand.”

10 Director Sam Taylor-Johnson Clashed With E.L James On-Set

Taylor-Johnson told The Guardian, “It’s hard when you get two headstrong people with very powerful visions that are so different. That was pretty tough, on both of us.” She also told the Sunday Times, “I like everyone — and I get really confused when they don’t like me. I was so confused by E.L. James.”

Related: Atlanta Movie Theater Accidentally Plays 50 Shades Freed Instead Of Black Panther

9 Jamie Dornan And Dakota Johnson Worked With A Sex Advisor During Production

Johnson told Marie Claire, “Jamie mostly had an advisor that was on set for the first film, not so much for the second. Then we just had people who specialized in knowing how things work, like how to use certain tools and toys.” She added, “There’s a certain method. It’s very intricate and the details are really important.”

8 A Social Media Spy Snuck Onto The Set Of Fifty Shades Darker And Pretended She Was A PA

During an interview with Cosmopolitan, “Fifty Shades Darker” director James Foley recalled, “She snuck on set and started doing little manual things like putting Cokes in the cooler. Finally, somebody started a conversation with her, and something seemed weird, and we discovered that she was a spy for a fan Twitter.”

7 Jamie Dornan Expressed Willingness To Do Fully Nude Scenes

Dornan explained to Entertainment Tonight, “I feel like if it serves a story to see more, then I am all for it. If I don't think it adds anything or I don't deem it to be necessary to move the story along, then I don't think you need to see that part of me, or that part of Dakota [Johnson].”

Related: ‘Fifty Shades Freed’: 15 Things You Need To Know Before Watching The Movie

6 There Was A Sex Scene Involving Vanilla Ice Cream That Got Left Out Of Fifty Shades Darker Due To Time Constraints

According to Foley, “There's nothing we left out on purpose. It was all simply about time.” He further explained, “You look at it and it seems pretty good. Then you screen it for an audience and it kind of lags in places, so you say, 'Oh, why did I leave that in there? And you change it.'"

5 When Shooting Sex Scenes, The Lead Stars Would Giggle

Foley revealed, “When we did the sex stuff, it's always kind of a little bit tense and people get shy — but then one of the other of them would giggle, and it was all OK, and it wasn't tense anymore. Some of [that] spilled into the movie.” He added, “When he spanks her, she giggles a little bit.”

Related: Here’s How Dakotah Johnson Got Insanely Toned For ‘Fifty Shades Freed’

4 While Filming Fifty Shades Darker, E.L. James Was Always Around With Her Own Producer’s Village

Foley revealed, “She had her own little producer's village and she was there every day. I really respected her for that. Like, she was looking after her baby.” An insider also told The Hollywood Reporter, “She was given a lot of power, and she used every opportunity to flex that power.”

3 The Spreader Bar Scene Was The Easiest To Film In Fifty Shades Darker

Foley revealed, “I came to the set, Dakota's in this great mood, like bouncing on the bed saying, 'Let's do this!' And we did it very quickly, and [Dakota and Jamie] were having a very good time. I mean, she was just giggling all over the place. So that one was easy.”

2 Dakota Johnson Struggled With The Elevator Scene In Fifty Shades Darker

Foley recalled, “It was a fake elevator. It was just a wall back there and we were all out here, so it wasn't too bad in terms of being cramped. But it was in terms of Dakota getting into it. [She] said that it was the hardest scene for her to shoot.”

1 There Was Reportedly A Salary Negotiation Among The Lead Stars For The Sequel

Both stars reportedly received $250,000 each and signed on for three films. However, they were expected to “renegotiate for seven-figure raises,” sources told The Hollywood Reporter. Meanwhile, producer Dana Brunetti remarked, “That was the great thing about this film — we knew we were going to be able to make stars. Now it's their opportunity to get paid on other projects.

Next: 15 Things Dakota Johnson Got Real About