When ‘The Testament of Ann Lee’ director Mona Fastvold approached Lewis Pullman for the part of William, Ann Lee’s loyal brother, it was the only role in the film he didn’t want. It would require him to sing, and he wasn’t a singer—he’d be appearing alongside Amanda Seyfried, who had already demonstrated her vocal prowess in Mamma Mia! and Les Misérables. “I was like, ‘I want to be a part of this. But I can’t be counted on to hold this story together.’ I was way too scared of playing William,” Pullman says. Fastvold insisted that she wasn’t looking for professional vocalists; this wasn’t a musical, but a historical drama about “human beings who sang a lot.” He mulled it over, worked on some sampled choreography with his mother, modern dance instructor Tamara Hurwitz, and filmed a few clips of himself singing and dancing to share with the director. Instead of discouraging her, the clips only reaffirmed Fastvold’s belief that he was right for the movie. So he took the leap. At the li...