Proof: According to The Hollywood Reporter, Hope Davis, who is garnering critical acclaim for her starring turns in American Splendor and The Secret Lives of Dentists, will join Gwyneth Paltrow and Jake Gyllenhaal in Proof for Miramax Films.

Also added to cast this week, Anthony Hopkins was annouced for a role in the film.

John Madden is directing the Hart Sharp Prods. project. Based on David Auburn's Pulitzer Prize- and Tony Award-winning play of the same name, the project is about a young woman (Paltrow) taking care of her dying father (Hopkins), a brilliant but insane math professor. Davis will star as Claire, the cynical, all-business sister of Paltrow's character who returns to her hometown.