11 things you didn't know about 'NCIS'

"Incognito" -- After a Marine is found murdered in Quantico hours after calling Gibbs to discuss a possible case, Bishop and McGee go undercover as a married couple to run surveillance on a Marine Lieutenant and his wife, on NCIS, Tuesday, Oct. 6 (8:00-9:00 PM, ET/PT), on the CBS Television Network. Pictured left to right: Michael Weatherly and Mark Harmon Photo: Colleen Hayes/CBS ©2015 CBS Broadcasting, Inc. All Rights Reserved (CBS)

"NCIS," the No. 1 drama on television, will return for its 14th season on Sept. 20 on CBS. Longtime cast members Mark Harmon, Pauley Perrette, Sean Murray and David McCallum will be joined by newcomers Wilmer Valderrama, Duane Henry and Jennifer Esposito, as the show moves off following the departure of Michael Weatherly (Tony DiNozzo).

But before the new season begins, check out these 11 fun facts that FOX411 sleuthed out about the crime drama:

1. 'JAG' inspired 'NCIS'

(Paramount)

"NCIS" was a spin-off of "JAG," starring David James Elliott and Catherine Bell. Both shows were created by Don Bellisario, who served as a Gunnery Sgt. in the U.S. Marine Corps from 1955 to 1959.

2. 'NCIS' was called what?

(Paramount)

"NCIS" was originally named "NCIS: Naval Criminal Investigative Service" to make it clear what the series was about in order to get viewers to tune in the first season.

3. Namesake

(CBS)

Special Agent Leroy Jethro Gibbs is named after Bellisario's father and grandfather.

4. Perrette's science background

"Reasonable Doubts" -- The NCIS team must ascertain who is lying, the wife or the mistress, after the women accuse each other of murdering a Navy Public Affairs officer, on NCIS, Tuesday, March 22 (8:00-9:00 PM, ET/PT), on the CBS Television Network. Pictured left to right: Brian Dietzen and Pauley Perrette Photo: Monty Brinton/CBS ©2016 CBS Broadcasting, Inc. All Rights Reserved (CBS)

It isn't a far stretch for Pauley Perrette to play Chief Forensic Scientist Abby Sciuto because in real-life, she studied sociology, psychology, and criminal science. She told FOX411, "I was super into school, and I got my master’s degree in criminal science because I wanted to be a cop before all this happened."

5. Family connections

"React" -- When Secretary of the Navy Sarah Porter learns her daughter has been kidnapped, the NCIS team partners with the FBI to track the case, determine a motive and bring her home. Alswo, McGee's (Sean Murray, center) childhood friend, NCIS Special Agent Valerie Page (Christina Chang, left), is in town to assist the team with advance tactics training, on NCIS, Tuesday, Feb 16 (8:00-9:00 PM, ET/PT), on the CBS Television Networkon NCIS, Tuesday, Feb 16 (8:00-9:00 PM, ET/PT), on the CBS Television Network. Pictured left to right: Christina Chang, Sean Murray, and Mark Harmon Photo: Neil Jacobs/CBS ©2016 CBS Broadcasting, Inc. All Rights Reserved (CBS)

Sean Murray, who plays Special Agent Timothy McGee, is Bellisario's stepson. Troian Bellisario, who plays McGee's sister Sarah, is Bellisario's biological daughter. More family members have guest-starred. Michael Bellisario played the role of crooked lab assistant Chip Sterling in Season 3, while Vivienne Bellisario (Bellisario's wife and Murray's mom) played the mysterious love interest of Leroy Jethro Gibbs (Mark Harmon) in Seasons 1 and 2.

6. Abby's drink

"Decompressed" -- When a deep sea diver is murdered on the job, his body and suspected co-workers must remain in a high-tech decompression chamber for four days, leaving the NCIS team to complete an unorthodox investigation from outside the tank, on NCIS, Tuesday, Feb. 9 (8:00-9:00 PM, ET/PT), on the CBS Television Network. Pictured: Pauley Perrette Photo: Michael Yarish/CBS ©2015 CBS Broadcasting, Inc. All Rights Reserved (CBS)

Abby's Caf-Pow energy drink doesn't exist in real life but you can buy a Caf-Pow cup or mug from the CBS online store. What Perrette actually asks to be put in the cup varies, but it is never an energy drink.

7. Most wanted

The NCIS Most Wanted Wall changes, but it is 15 portraits of the bad guys that the team is after. In the past it has included Ari Haswari (Rudolf Martin), Rene Benoit (Armand Asante) a.k.a La Grenouille, Harper Dearing (Richard Schiff), and even real life terrorists such as Osama Bin Laden, whose portrait was X'ed out with red tape when he was killed. But the show also has a sense of humor and Bellisario's photo also hung among the gallery of most wanted.

8. De Pablo is dedicated

"Squall" -- A massive storm brings the NCIS team aboard the USS Borealis, where everyone becomes a suspect once the crime scene proves that Mother Nature wasn’t the only culprit. Tension builds when McGee discovers that his estranged father, Navy Admiral John McGee, was on board during the incident, on NCIS, Tuesday, March 26 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Pictured: Cote de Pablo Photo: Sonja Flemming/CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved. (CBS)

In order to play Israeli, de Pablo, who when she first joined the cast was a Mossad agent, hired a language coach to help her whenever she needed to speak Hebrew.

9. Holly wanted to play Kate

Actress Lauren Holly arrives on the red carpet at the 2014 Canadian Screen awards in Toronto, March 9, 2014. REUTERS/Mark Blinch (CANADA - Tags: ENTERTAINMENT) - RTR3GCZO (Reuters)

Lauren Holly auditioned for the role of Kate, but the producers thought she was as a better fit as the in-charge director Jenny Shepard.

10. Flashbacks

When Gibbs appears in flashbacks as a young man, the role is played by Harmon's real-life son, Sean.

11. Real-life NCIS

Even though "NCIS" is set in Washington, D.C., it films in Santa Clarita, Calif., just north of Los Angeles. But, in at least one episode, the real NCIS headquarters appears in the background.

The one secret that has yet to be revealed is how Gibbs gets the boats he builds in his home basement out of his house once they are finished.