It took more than a pair of colored contacts to transform Kristen Stewart’s “Twilight” character, Bella Swan, into the vampire Bella Cullen. As the 22-year-old actress explains that she had to ditch the quirks that came naturally to her in order to portray an assured, super-strong and speedy vamp. “I’ve yet to play somebody who was a huge departure for me. I mean, to be completely still and controlled, and to know that your mind works faster,” Stewart said of the character transition. “Being a clumsy person, it’s not the easiest thing to do. The way I usually learn my lines is I learn the idea, which is why I stutter a lot in ‘Twilight.’” For Twilight Fans: “The Twilight Saga: Breaking Dawn – Part 2” will be released on Blu-ray, DVD, digital download and video on demand March 2.