Actress Summer Glau will appear as a guest star on the NBC spy series Chuck, according to Ausiello Files.

The Terminator: The Sarah Connor Chronicles star will appear as Greta, an undercover agent character who will be portrayed by a different actor in each episode of Chuck's fourth season. Olivia Munn portrayed Greta on Monday's Season 4 premiere episode, and other confirmed Greta's this season include Stacy Keibler and Old Spice pitchman Isaiah Mustafa.

RELATED: Chuck Series Finale Clip

Summer Glau will appear in the eighth episode of Chuck this season. The actress will also return to NBC in midseason with a role on the superhero series The Cape.

We'll be sure to keep you posted with any further news about upcoming Greta's on this season of Chuck as soon as we have more information.