The guest star heavy fourth season of Chuck gets underway on September 20... in gorgeous fashion.

Olivia Munn comes aboard the NBC series in the role of CIA operative Greta, a role that will actually change throughout the season and later be played by Stacy Keibler and Isaiah Mustafa.

In the premiere pics below, it's clear the Burbank Buy More has recovered from last season's events, thanks to help from the CIA, which will be running the store this fall. Check out a couple photos from "Chuck vs. the Anniversary" and visit our Chuck spoilers section for a more thorough look at season four:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.