Spoiler alert: 'Twilight' fans love shocking ending

• 'Breaking Dawn, Part 2' features a surprise ending not in Stephenie Meyer's book
• Twi-hards went through shock seeing the scene at first, but have loved it enough to make the final movie a box office monster

Spoiler alerts for anyone who has not see Breaking Dawn!

The Twilight Saga: Breaking Dawn, Part 2 takes a wild turn from the book at the end of the film, and Twi-hards are loving it. Going into its second week of release, the film has already made $151 million and looks to dominate over the Thanksgiving holiday.

Big twists are generally a big no-no in the Twilight series, based on the near-sacred text from Stephenie Meyer's novels. But in this case Meyer wanted to make the big change, an epic battle that never took place in the final book.

"That was a major sticking point for Stephenie about making the fourth (Twilight) book into a movie," says screenwriter Melissa Rosenberg. "She knew it was not a cinematic ending. The book had no physical confrontation. She knew that would have to change. But she didn't want the storytelling to change."

During the filming of Eclipse, the third movie in the series, Rosenberg and Meyer had dinner and Meyer suggested a battle sequence.

"It's like this light bulb went on," says Rosenberg. "It was one of those moments."

The battle concept, which has yet another big twist at the end, features plenty of heads ripped off and was worked into the film.

Taylor Lautner sat in the Nokia Theatre in Los Angeles during the Breaking Dawn premiere Nov. 12 and saw Twi-hard reaction firsthand.

"While the surprise was happening they were terrified — out of their minds freaking out," says Lautner. "The shrieks and screaming. It was crazy."

Kara O'Grady of TwilightMoms.com says she too saw the reaction of surprise from the fans. But like most Twilight fans, she gave it the thumbs-up once it played out.

"The movie version added a new spin," says O'Grady. "We all know the books inside and out so it was great to have a surprise heart-stopping twist."

Even more exciting for O'Grady was seeing each of the major Twilight characters take a screen curtain call in the film.

"My favorite part of the movie was the farewell montage," says O'Grady. "Showing all the actors involved from the beginning. It was a wonderful retrospective of the last five years — a perfect fond farewell to the books and movies that have truly changed my life for the better."