Those who can't wait for the September 20 premiere of "Chuck" season 4 can delve into the five clips released by NBC. Not only revealing the new CIA headquarter, the clips from episode "Chuck Vs. the Anniversary" give away for the first time Olivia Munn and Dolph Lundgren in their guest starring roles.

Munn is playing Greta, a master of disguise working for CIA, who will be played by different actors every week. Lundgren meanwhile is playing Marco aka the villain in the season opener who kidnaps Sarah and Casey in Moscow, Russia.

"Terminator" actress Linda Hamilton is also a recurring character, playing Elizabeth Bartowsky. Chuck's relationship with superspy Sarah Walker is getting serious and he's about to take on his most personal mission yet: finding his mother. Chuck's assignments take him far from Burbank, with each mission bringing him closer to uncovering what happened to his mom.