"Chuck" is not stopping any sooner to invite notable guest stars into its season 4. The Greta storyline where a different actor would portray the master of disguise each week has enabled the show to tap Olivia Munn, Stacy Keibler and Isaiah Mustafa so far. And the show has just scored a jackpot with Summer Glau.
Known to nerds as the sexy and friendly terminator in "Terminator: The Sarah Connor Chronicles", Glau would take over Greta in the eighth episode which would air sometime in November. Since "TTSCC" was canceled, Glau herself has taken a part on NBC's new series "The Cape". But she won't need to do promotional appearance any sooner for it is reserved for midseason 2011.
On another casting news from NBC, Hilary Duff is paying "Community" a visit as one of the "Mean Girls". Entertainment Weekly heard from a source that Duff would be the queen bee in the rivalry against the Scoobies. The episode can be expected in November sweeps.