Scream sequels is commonplace, and I'm sure if you asked director Wes Craven before filming began on the fourth movie four days ago - he would tell you that things never run 100% smoothly when he is dealing with the Ghostface killer. There's been more last minute cast drop-outs this week, never ideal when the camera's are already rolling. THR say Lake Bell and Gilmore Girls' Lauren Graham have both dropped out, citing a mixture of scheduling difficultieis and (0h dear) last minute script changes but maybe that's not entirely accurate. It's said that Craven has only given cast members a limited amount of Kevin Williamson's script and he isn't letting them see past a certain point, so maybe they are just being fed scraps everyday and Graham didn't like how her character unfolded when it was eventually revealed to her. Craven has moved quickly to replace the drop-outs - bringing Grindhouses' Mary Shelton in to replace Bell as the cop who knows Sidney from way back, and The Wrap says vet actress Mary McDonnell to replace Graham as lead Emma Roberts' mother. More new faces have also been added this week; Adam Brody (who feels like a Scream actor, no?) will play a cop recently graduated from college who was raised on the CSI TV series. He played a cop in Kevin Smith's Cop Out... Erik Knudsen (Youth in Revolt, Scott Pilgrim vs the World) will play the second movie-obsessed geek of the film, playing a new take on Jamie Kennedy's character from the original. Community star Alison Brie will play Rebecca, "ambitious personal assistant" to Neve Campbell's Sidney. Alongside Neve, Courtney Cox and David Arquette reprise their roles from the trilogy, but this time as supporting players. Emma Roberts leads as Jill Kessler (cousin to Sidney), Hayden Panettiere as Kirby Reed (nerdy film geek and Jills best friend), Rory Culkin (as Charlie, a love interest for Jill). Gossip Girls Lauren Graham (as Jills mother), Nico Tortorella (Trevor high-school jock), Anthony Anderson (as a cop) support, along with a bunch of unknowns. Scream 4 is filming now, for a release next April.