This may be the final nail in the coffin for Up All Night: After being pursued by CBS for several days, Will Arnett has officially been cast in producer Greg Garcia's untitled comedy pilot for the Eye network. He'll play a newly divorced dude named Jack who finds himself dealing with his own parents' marital woes. Technically, Arnett's casting will have no impact on the fate of Up: If NBC decides to bring the show back next fall, contractually Arnett would have to give up the CBS project. That said, big stars like Arnett rarely bother to do new pilots if they think there's much of a chance their shows will be coming back. As it is, Christina Applegate has already departed Up, as has original creator Emily Spivey. No word yet from NBC about whether it still plans to go through shooting its Up revamp.