Casting Net: Sigourney Weaver, Joan Cusack, James Marsden

• The franchise business can be a funny one. Save for a few clips here and there, the world has yet to see — let alone weigh in on — the first film adaptation of Cassandra Clare’s The Mortal Instruments series, which opens on August 21, but the filmmakers are already gearing up to start shooting the second installment in October. Sigourney Weaver is in negotiations to play one of the few new roles that appear in City of Ashes, the second book in Clare’s series about a normal girl (played by Lily Collins) who finds out she’s actually a Shadowhunter, or, a race of sort-of humans who protect the world from werewolves, vampires, and other mystical creatures. Weaver would play the leader of the Shadowhunters out for vengeance against the man who killed her son. [THR]

• Joan Cusack (The Perks of Being a Wallflower), James Marsden (27 Dresses), Wes Bentley (The Hunger Games), and Alan Tudyk (42) have joined the cast of Welcome to Me, starring Kristen Wiig as Alice, a woman with a borderline personality disorder who starts her own cable access show about herself with her lottery winnings. The Will Ferrell and Adam McKay-produced comedy began production on Monday, with Shira Piven (Fully Loaded) directing. [Deadline]

• John Robinson is the latest actor to join the ensemble cast of Peter Bogdonavich’s Squirrels to the Nuts, starring Owen Wilson and Jennifer Aniston. Robinson’s first role was in Gus Van Sant’s Elephant, and has since appeared in a wide array of movies including Wendy and Lucy and Transformers. [The Wrap]