Amanda Seyfried "had so many nightmares" about acting with a Mancunian accent in The Testament of Ann Lee. In her new historical drama musical, the Mamma Mia! actress plays the title character, who founded the Christian sect, the Shakers, and emigrated to the U.S. from Manchester in 1776. Seyfried admitted to Variety that she was so concerned about the accent, she asked director Mona Fastvold why she wanted to cast her instead of an English actress. "(The accent was) incredibly difficult. I had so many nightmares about people being like: What the f**k is she saying? My job is to keep you completely committed to the story. And my fear was that it wasn't gonna work. Which is why I kept saying to Mona, don't you want to get an English person?" she shared. "I was like, 'Are you sure you want me, Mona, are you sure? Surely there are other younger British actresses who could nail the accent.' But she said: 'God no, you can get this made for me!'" Seyfried then revealed that she watched footage of actress Maxine Peake, who hails from Greater Manchester, to help perfect the accent. "She was my beacon... And the internet had her on a silver platter for me," she said, adding that Peake doesn't know she was her inspiration. The film also marks the first time Seyfried has sung on film since 2018's Mamma Mia! Here We Go Again, but she noted that it was more like "anti-singing" this time around because she wasn't supposed to sound beautiful. "A lot of it was animal sounds as opposed to melodic sounds," she explained. "It was more like a woman on her knees. And it was f**king hard. We did the birthing song Human Treasures so many times because I had to release my s**t, my ear, my needs, Amanda's needs, in order to find the voice that held the passion, the rawness, the grief and the desperation." The Testament of Ann Lee premieres at the Venice Film Festival on Monday.