'Chuck' pics: First look at Linda Hamilton, plus more Olivia Munn

linda-hamilton2.jpgWe're now less than three weeks away from the return of "Chuck," and NBC has released a few more pictures from the season premiere -- including the first shots of Linda Hamilton as Chuck's ( Zachary Levi) mom.

That's Mama Bartowski up above, of course, looking much as she did in the show's on-air promo from a few weeks ago. We're going to go ahead and guess that she's in a lair of some sort, given the big computer desk and dim lighting. We don't yet know much about what she's up to, but it appears she does know how to handle a gun. We'd expect nothing less from the original Sarah Connor.

linda-hamilton-chuck-horiz.jpgThe new batch of photos also includes our first look at Casey ( Adam Baldwin) and Sarah ( Yvonne Strahovski) in Season 4. Chuck himself is no longer a government employee as the season starts, but Sarah and Casey are, and we're assuming the private jet they're on in the shot below has something to do with work.

casey-sarah.jpgFinally, we have a couple more shots of Olivia Munn as CIA operative "Greta," who's undercover as a Nerd Herd employee at the Buy More. As in the first-look photos we posted last week, she's interacting with Chuck and Morgan ( Joshua Gomez) -- but take a look at the background in the last shot as well, because we think it offers further evidence that the Buy More is now an agency front. See that woman in the Buy More sales uniform? Yeah -- we don't remember any greenshirts looking like that in the past.

greta-morgan-chuck.jpg greta-morgan.jpg"Chuck" premieres Monday, Sept. 20 on NBC.

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Photo credits: NBC