How JAG Connects To NCIS, Five-0, NCIS: LA, NCIS: New Orleans, MacGyver, Magnum, Scorpion And NCIS: Hawai'i

When it comes to JAG and the forever-expanding NCIS Universe that it begat, "It's all connected" (if we may borrow a phrase from Marvel TV's Jeph Loeb).

A spinoff of JAG, the NCIS mothership on March 28 will crossover with its own latest offshoot, NCIS: Hawai'i, in back-to-back episodes that send Special Agents Nick Torres and Jessica Knight to the Aloha State (with a couple other NCIS cast members appearing if not going along for the ride).

NCIS: Hawai'i had its first quasi-crossover of sorts when an early episode of the freshman CBS drama revealed the role that none other than Leroy Jethro Gibbs played in nudging along Jane Tennant's own career as an NCIS Special Agent. But the official two-part crossover event will solidify NCIS: Hawai'i's place in the Extended JAG/NCIS Universe (JNCISU?).

On this special occasion, TVLine revisits many of the ways that JAG and NCIS characters have visited other CBS series (including one instance you might have forgotten about!), either in one-off or recurring guest spots, or in one- or two-way crossover events.

Which of these crossed streams/character team-ups do you most fondly recall?

NCIS' backdoor spinoff pilot came in the form of a JAG Season 8 two-parter, in which Special Agent Gibbs' team investigated the murder of a lieutenant — and Commander Harmon "Harm" rabb Jr.'s possible role in it. In addition to Mark Harmon, future NCIS cast members Michael Weatherly, Pauley Perrette and David McCallum appeared in the planted pilot, as Tony, Abby and Ducky.

In the years since, JAG characters such as Harm, Lieutenant Colonel Sarah "Mac" MacKenzie, Lt. Bud Roberts and Rear Admiral A.J. Chegwidden have popped up on NCIS: Los Angeles and or NCIS.

Fun fact: NBC pretty famously bailed on JAG after one season, at which point CBS "saved" the military/legal drama and eventually spun it off into a 40-season (and counting?) NCIS franchise.

In addition to the backdoor pilot episodes that eventually sired NCIS: Los Angeles (at the end of Season 6) and NCIS: New Orleans (near the end of Season 11), NCIS has received visits from JAG characters such as Lt. Bud Roberts (played by Patrick Labyorteaux, pictured), Rear Admiral A.J. Chegwidden (John M. Jackson) and Faith Coleman (Alicia Coppola).

Next up: NCIS Hawai'i Special Agent Jane Tennant (played by Vanessa Lachey) helps kick off NCIS' two-part crossover with its latest spinoff.

In addition to receiving early-on visits from NCIS' Abby, Tony (pictured) and Director Leon Vance, NCIS: LA in Season 3 had a two-way crossover with Hawaii Five-0's Danny Williams and Chin Ho Kelly (played by Scott Caan and Daniel Dae Kim), while Kensi went stag to Five-0 during its second season.

More recently, JAG leads David James Elliott and Catherine Bell reprised their roles as Harm and Mac for an arc at the end of LA's 10th season, while John M. Jackson has thus far made a half dozen appearances as JAG's Chegwidden.

In addition to the aforementioned Season 2 visit from NCIS: LA's Kensi (who was enlisted by Joe White to review a video of John McGarrett with Governor Jameson and Wo Fat), Five-0 had a full-on two-way crossover with NCIS: Los Angeles the following season.

Five-0 also had a two-way crossover with Magnum P.I. (detailed in the latter show's slide below), and Daniel Dae Kim, Grace Park and Taylor Wily once guest-starred on MacGyver as Chin Ho, Kono and Kamekona.

The Season 1 episode "Flashlight" saw Mac & Co. get an assist from Hawaii Five-0's Chin Ho Kelly and Kono Kalakaua, with Kamekona also putting in an appearance.

Also, after Five-0 had signed off, Jorge Garcia popped by MacGyver as conspiracy theorist Jerry Ortega, reuniting the actor with fellow Lost alum Henry Ian Cusick.

NCIS: New Orleans during its seven-season run enjoyed visits from NCIS characters such as Ducky, former FBI agent Tobias Fornell (played by Joe Spano), CGIS Special Agent Abigail Borin (Diane Neal, pictured) and SECNAV Sarah Porter (Leslie Hope).

P.S. Bring back Borin, NCIS-verse!

Early into Scorpion's freshman run, NCIS: Los Angeles front woman Linda Hunt guest-starred as Hetty Lange, who was recruited to help Walter's team look the part as they went undercover to protect a priceless art exhibit.

In addition to its two-way crossover with fellow island drama Hawaii Five-0 – which involved Alex O'Loughlin, Meaghan Rath, Katrina Law and Beulah Koale as Steve McGarrett, Tani Rey, Quinn Liu and Junior Reigns — Magnum is no stranger to guest appearances by the likes of Kimee Balmilero as Dr. Noelani Cunha, Dennis Chun as Sgt. Duke Lukela, Taylor Wily's Kamekona and Shawn Mokuahi Garnett's Flippa.

(As for the issue of the Magnum, P.I. TV show's theme song having once been sung by Five-0 characters, that was "explained" here.)

In Part 1 of the two-way crossover — airing Monday, March 28 at 9/8c and titled "Starting Over" – NCIS' Special Agent Nick Torres (played by Wilmer Valderrama) gets invited by NCIS Special Agent Jane Tennant (Vanessa Lachey) to come to Hawai'i, when she gets a lead on a witness from a case they worked on together.

In Part 2, airing at 10pm and titled "T'N'T," Katrina Law's Special Agent Jessica Knight treks to Hawai'i herself, while Gary Cole's Alden Parker and Diona Diona Reasonover's Kasie also make appearances.

Press play above for our video Q&A with Katrina Law about the crossover.

Want scoop on any of the above shows? Email InsideLine@tvline.com and your question may be answered via Matt's Inside Line.