And so the lion fell in love with the lamb … and 17 million fans devoured every page.

Twilight, the insanely successful series of young adult novels about 17-year-old Bella Swan’s romance with immortal vampire Edward Cullen, arrives on the big screen with a rapturously devoted audience, many of whom were extremely unhappy with the film’s casting after imagining the books for years.

“I felt an immense responsibility to the character,” Kristen Stewart, who stars as Bella, admits. “I didn’t realize that people cared about it as much as I did. Rob [Pattinson] had gone online and seen that people were outraged by his casting and mine, too, and we thought, ‘Wow. Why?’”

“My mum sent me some stuff that she thought was really funny,” newly minted heartthrob Robert Pattinson, who plays Edward Cullen, recalls. “A site had this picture from a Viking film I’d just done where it looks like someone had beaten me in the face with a frying pan and I’m wearing this disgusting wig. It said ‘THIS is Edward’ and [the fans] had a petition, which they were going to send to the studio saying, ‘We will NOT go see your movie with him in it.’ It got up to 75,000 signings, and this was like three days after I got cast. That was my welcome into Twilight.”

The best-selling novel’s author, Stephenie Meyer, knew bringing the film to the big screen would come with tremendous responsibility both to her devoted readers and to the vision she’d held in her own brain for so many years.

“I was braced in case it was horrid,” Meyer says, describing how she felt when she sat down to watch the film for the first time. “I was watching through my fingers. I had my little notepad because it was a rough cut and I was supposed to give my notes but, after a few minutes, you start getting into Kristen’s voice, and it starts becoming Bella’s voice and it got to where I completely forgot why I was there.

“There were so many scenes that were like déjà vu,” Meyer smiles. “When the movie was over, the producer was there and she said, ‘OK! Give me your notes,’ and I said, ‘Give me a minute.’ I was so overwhelmed. So many scenes were just as I’d envisioned them. It was partially creepy and partially wonderful.”

Catherine Hardwick, the film’s director, can be thanked for the movie’s faithful actualization.

“I knew [Catherine] was the person whose focus was going to shape the film and so, if she had different ideas from me, it wasn’t going to turn out very much like how I’d seen it in my head,” Meyer says. “But we were on the same page from the very beginning. Things that I was worried about she was already on top of and it was exactly what I wanted.”

Pattinson was a different story, performance-wise.

“With Rob, we sat down and talked out Edward’s character before filming started, but we actually disagreed on his character,” Meyer laughs. “I’d say ‘This is how it is,’ and he’d say, ‘No, it’s definitely this way.’ The funny part about it is, here we are, arguing about a fictional character, yet in the performance, he did what he wanted and yet it was still exactly what I wanted.”

The filmmakers hope fans will have a similar experience with a story they treasure.

“It represents everything you go through at that age when everything is entirely heightened,” Stewart says. “It’s a dire, wrenching story because it’s not an easy love. I feel very proud of the movie. We couldn’t have worked any harder.”

Twilight releases in theaters Nov. 21.