In a move that made fanboys and geeks everywhere swoon, NBC has announced that The OC's Rachel Bilson will reunite with series creator Josh Schwartz on a multiple-episode story arc on new fall dramedy Chuck.

Bilson's first appearance is scheduled for some time in October. The actress, who played Summer Roberts on FOX's The O.C. under Schwartz's watchful eye, will play a new potential love interest for Zachary Levi's Chuck.

"Rachel's been traveling all over the world shooting a big Doug Liman action-movie Jumper, and she was going to be in Los Angeles for a little while," said Chuck co-creator Schwartz. "We were talking and thought it would be fun to work together again, even for a few weeks. Having worked with her for four years, I know how funny Rachel is and what a good match she'd make for the show, and for Zach Levi. For a first-year series, it's really hard to get big name guest stars, so we're all really excited and grateful that she could do this."

So just what sort of character will Bilson be portraying? Apparently, Chuck's potential squeeze is a sandwich maker who likes magic and seems to be a sweet girl. But, given Chuck's current situation (what with all the government secrets locked in his brain) is Bilson's character really who she appears to be? Find out this fall.

Chuck launches Monday, September 24 at 8 pm on NBC.

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Jace is an LA-based television development and acquisitions exec who watches way too much television for his own good and would love a TiVo for every room in the house. (He’s halfway there.) His blog, Televisionary, can be found at televisionaryblog.com.