Alphabet Troupe

For McCallum, best known as charming superagent Illya Kuryakin in the 1960s series The Man From U.N.C.L.E., their anonymity is the show's greatest strength. ''It's like an undiscovered treasure,'' says the actor. ''We have the opportunity to exploit that.''

In order to draw viewers beyond just JAG freaks, CBS would be wise to exploit the head-turning cast, which features male sex symbols from three different generations. ''We did the up-fronts in New York, and all the ad buyers were there,'' says Weatherly, a former soap star. ''These chicks went bananas for Mark Harmon. I mean, like Tom Cruise/Brad Pitt bananas.''

Still, Bellisario wasn't initially sold on Harmon when his name first came up for the part of Gibbs. ''Quite frankly, I said, 'What have I seen him in [lately]?''' he admits. But Harmon's 2002 Emmy-nominated guest stint as a Secret Service agent on The West Wing changed that. ''They gave me the [tapes], and I went, 'Oh, wow, that's the character! That's him.''' Harmon, a veteran of hospital dramas St. Elsewhere and Chicago Hope (as well as two relatively short-lived detective series, Charlie Grace and Reasonable Doubts), is now enjoying a career resurgence that includes a role in the late-summer hit Freaky Friday and a turn as the President opposite Mandy Moore in an as-yet-untitled 2004 film. ''Life kind of goes in peaks and valleys, and it certainly doesn't read like a resume,'' says Harmon, 52, during a lunch break on set. ''I don't get too excited about the high points and I don't get too excited about the low ones. I'm just thankful not to be wearing scrubs.''

Finding NCIS' female lead also took a little legwork. In the crossover JAG episodes, Savannah's Robyn Lively played a former FBI agent named Viv Blackadder. But Bellisario says the role wasn't a perfect fit. ''To be fair to her, she was only cast the night before we started,'' says Bellisario. ''She had no time to prep, and she just never could really get a grasp on who the character was. I wanted a real mix of balls and femininity. She can play the femininity very well, but she had a little trouble with the other part of it.'' He found a woman who could provide both facets in Alexander, who experienced quite a culture shock coming from the estrogen-heavy Presidio Med. ''The first day on the set, I turn around and it's just me and all these men around me,'' remembers Alexander, whose Secret Service agent decides to join NCIS in the first episode. ''And I'm the lonely little woman. Even my hair and makeup [people] are men on this show! But I call them my ladies anyway.''

What to call the show itself is another story. CBS first announced the title as NCIS, but, concerned that audiences wouldn't know that the N stood for Navy, soon switched it to Navy CIS and then Naval CIS. But that acronym elicited a too-close-for-comfort complaint from CSI exec producer Jerry Bruckheimer, so the network settled on the redundant Navy NCIS (spelled out, that's Navy Naval Criminal Investigative Service). ''Nobody involved with the show calls it anything except NCIS,'' says Perrette. ''It's very frustrating. There's a real thing called NCIS. There are real agents called NCIS agents. We know these people. So I find it a bit disrespectful to say, 'Okay, we're going to change the name, because we're afraid [viewers]are going to get confused.'''

Bellisario expects that if the series lasts, they'll drop the Navy and be known simply as NCIS. But until then, he's got to convince us all that his latest creation is more than just the sum of two others. ''I want it to be a different show,'' he reiterates. ''It's not JAG and it's not NCIS -- I mean CSI. And I want to make that clear.'' Apparently, that's easier done than said.