Stephenie Meyer
Stephenie Meyer, pictured at the Women In Film 2015 Crystal + Lucy Awards, June 16, 2015, in Century City, California, wrote more than 400 pages of bonus content for the 10th anniversary of "Twilight." Getty

When 2012's "The Twilight Saga: Breaking Dawn -- Part 2" hit theaters, it looked like that would be the end of the series. However, author Stephenie Meyer announced in September she would be releasing a 10th anniversary edition of the first "Twilight" book that would have new content. Fans were stunned to learn Tuesday that she flipped the genders of the main characters in "Life and Death: Twilight Reimagined." The new content includes a story about a character named Beau, the male version of Bella Swan, and Edythe, the female version of Edward Cullen.

In an interview with "Good Morning America" Meyer said she wanted to do something fun for the anniversary of the popular young adult book series. The bonus content wasn't originally going to be long, but once she got going, it was "fast and easy" to write, she said. Meyer is curious how fans will react when they look at Bella as Beau.

"I do feel like it’s really very much the same thing, so I guess my hope is that maybe the younger readers will be reintroduced because a lot of my readers, you know, they’re all 10 years older now and so there’s a whole new generation," she said.

Meyer decided to take on the gender role reversal after many commented Bella was a "typical damsel in distress" in the "Twilight" books. Meyer said she felt it could be fun to test this idea in the anniversary edition.

“My answer to that has always been that Bella is a ‘human in distress,’ a normal human being surrounded on all sides by people who are basically superheroes and villains. … I’ve always maintained that it would have made no difference if the human were male and vampire female -- it’s still the same story,” she wrote in the book's forward.

"Twilight" was the first installment in the popular YA series. It was followed by the novels "New Moon," "Eclipse" and "Breaking Dawn." The books have chalked up more than $150 million in sales worldwide and spent 235 weeks on the New York Times Best Seller list.

The book series also led to a major film franchise called "The Twilight Saga." Five films were made from 2008 to 2012 starring Kristen Stewart (Bella Swan), Robert Pattinson (Edward Cullen) and Taylor Lautner (Jacob Black). All five movies grossed over $3 billion worldwide.

"Life and Death: Twilight Reimagined" hits stores Tuesday.