Mark Harmon and Scott Bakula

The latest installment in the NCIS franchise, NCIS: New Orleans, premieres this fall on CBS. But viewers have already gotten an introduction to the crew down in the Big Easy thanks to a two-part episode that aired this spring as part of the original NCIS.

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Though NCIS: NOLA was originally conceived as a standalone two-part episode, as soon as executive producerGary Glasberg and NCIS leading man Mark Harmon went down to New Orleans to get a feel for the location and the characters, they realized they had a whole series on their hands.

In the video below — which is exclusive to TVGuide.com and will also be available as part of the NCIS Season 11 DVD set, out Tuesday — Glasberg and other members of the show's production team explain how the two-part episode came together, and offer a behind-the-scenes look at the planning process that went into creating NCIS: New Orleans.

NCIS and NCIS: New Orleans air their season premieres back-to-back on Tuesday, Sept. 23 starting at 8/7c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)