The members of the punk-pop trio Green Day are beginning work on what is being described as a "B-movie horror film," in which the group will star as well as provide music, according to group spokeswoman Amanda Cagan. "They're working [on] putting together writers for the script, but they don't know who they are yet," Cagan said, adding that the director, studio and title have not yet been announced. The trio, planning to release a soundtrack album to the project, approached No Doubt singer Gwen Stefani about appearing in the film, but it is not yet clear whether she will accept.