But the 27-year-old heartthrob has revealed in the first issue of Document magazine that he did not like Melissa Rosenberg's first screenplay adapted from Stephenie Meyer's novel.
"I didn't like the script," Kellan said matter-of-factly. "How scary would a glimmering vampire really be? It just didn't make sense."
But with the first four movies bringing in over a billion dollars at the box office and screaming fans at his every turn, Kellan is surely thankful that he jumped on board the Twilight train, not least because of his recent Lamborghini purchase.
But Kellan explained that he was also wary of the role because he had just finished filming HBO's Iraq War series Generation Kill in Africa where he witnessed some unsightly things which put life in perspective.
"You're seeing all of these murals with little girls bleeding, saying, 'Please don't rape me. I won't cure your AIDS'; you see people with no water, people taking baths in dirty rivers," he shared. "That project matured me five years and it really just spoke to my heart."
Kellan is now one of the most well known faces in the movie industry but he says one of his best experiences shooting a movie was before the first Twilight film was released.
"I gotta say my favorite moments were during… the first movie, before any of this craze happened," he told Us.
"We were just ourselves, no one really knew who we were yet. I remember Peter Facinelli and Jackson Rathbone and myself would go to different bars and different concerts… We'd go do karaoke all the time."
The final installment in the Twilight franchise hits theaters on November 16.