Actors You Forgot Guest-Starred On NCIS

NCIS has been on the air since 2003, and is currently in its 17th season. Yet still, years after year, it claims the title of "most watched series" on any given week. Not bad for a show that is itself a spinoff of another show, JAG — but then, JAG was successful enough to earn 10 seasons!

Due to its longevity and popularity, NCIS has seen its fair share of guest stars over the years. Some have held down recurring roles throughout numerous episodes, like Jon Cryer, who loved the show so much, he leveraged his popularity on Two and a Half Men to help him secure a role on NCIS. Others just pop up for a single episode, spending an hour of time with Mark Harmon and the rest of the team before going off on their way.

These are some of the biggest celebrities who have appeared on NCIS, dating all the way back to the beginning of the series. Prepare to be enticed into a marathon re-watch!

Bob Newhart makes a single appearance on NCIS in season eight episode "Recruited." Already a household name from sitcoms like The Bob Newhart Show and Newhart, his casting on NCIS was a bit of a swerve. Although NCIS has had plenty of humor over its many seasons, Newhart's role was a chance for the vaunted comedic actor to explore a bit more of his dramatic side.

Newhart plays Dr. Walter Magnus, who served as the NCIS medical examiner before Ducky. The episode revolves around an assault at a high school's college fair, but it focuses more on Magnus' relationship with Ducky, as Ducky apparently has pretty big shoes to fill. That isn't to say Newhart doesn't get his chance to show his comedic timing off — or call back to bits from his old sitcoms — but the episode focuses much more on the character making sense of rapid change. He hasn't been forgotten, but in today's fast-paced world, he has been thoroughly left behind. All in all, Newhart's appearance on the show is touching, and a great reminder that he is much more than just a funnyman.

Long before he became a superstar famous for playing good-hearted basketball players and, uh, Ted Bundy, Zac Efron had a very small role during season three of NCIS. He appears in "Deception," where he plays a snobby teenager who is brought in for questioning regarding a cell phone he'd been using. Naturally, the phone is linked to a much bigger case involving a kidnapped Lt. Commander, a shipment of nuclear weapons, and a predator she might have been tracking. The NCIS team listens in on Efron's character Daniel as he discusses who he got the phone from, which turns out to be the key to cracking the case wide open.

Efron had appeared in a few other small roles before NCIS, including CSI: Miami and ER. However, his appearance on NCIS was his last role before his big leap into the mainstream via High School Musical. Even though his part on the show is small, it isn't hard to see the charisma and star power that would go on to propel Efron to stardom. The showrunners were clearly on to something big.

Timothy McGee, played by Sean Murray, is one of the most frequently appearing characters on NCIS. Only two other actors have appeared in more episodes of the show: Mark Harmon and David McCallum, who have appeared in every single episode, putting McGee in pretty good company. It's fitting, then, that the showrunners needed a big name to play McGee's grandmother. Enter Lily Tomlin, just the woman for the job.

In some people's estimation, Tomlin is one of the most talented actors to have ever turned up on the show. Tomlin appears in the season nine episode "The Penelope Papers," playing McGee's grandmother and a central suspect in the case of the week. Tomlin has always been great at leading the viewer on, making one wonder what secrets she's hiding — this is a talent on full display throughout the entire episode. Her appearance is one of the best guest appearances in all of NCIS history, and hopefully she'll get a chance to return at some point before the show's over.

Many child actors see their careers stall before they reach adulthood. Their skills don't develop, they burn out from the tireless pace of the industry, or they just decide to head in another direction. Abigail Breslin is not one of those actors. From an early age, it was obvious her talent far outstripped being a cute kid — a fact NCIS knew before most. Two years before she had her big break in Little Miss Sunshine, Breslin turned in an impressive performance on NCIS when she was only eight years old.

Breslin appears in the season two episode "See No Evil," where she plays a brilliant young pianist named Sandy who, along with her mother, is kidnapped for ransom. Especially when you consider her age, Breslin's performance in this episode is masterful. Not only does she successfully convey the terror of being kidnapped, she convincingly plays a blind character.

What I Like About You and Signs claim earlier Breslin roles than her turn on NCIS, but are comparatively meager shows of her talent. In many ways, NCIS provided Breslin with one of her first major roles — one that, years later, holds up.

Colin Hanks has evolved into much more than just "Tom Hanks' kid" since first appearing alongside his dad in That Thing You Do! back in 1996. He has shown a wide theatrical range across movies and television, and his multi-episode run on NCIS allowed him to showcase those talents.

Hanks first appears in the second-to-last episode of season ten, "Double Blind," as an investigator for the Department of Defense named Richard Parsons. Parsons is brought in to investigate Gibbs and the rest of the NCIS team over a specific case, but it is gradually revealed that he has a personal grudge against Gibbs for the way he has operated over the years. Eventually, he realizes that Gibbs and his team are doing things correctly, and backs off.

Hanks makes quite an impression over the few episodes he appears in. His ability to play a manipulative and menacing character who turns out, in the end, to be on the side of the angels, makes for an exciting transition between seasons ten and eleven and an unforgettable character.

That's right — Lando himself appears in not one, but two episodes of NCIS. Billy Dee Williams first appears in a season ten episode entitled "The Namesake," then in season eleven's "Honor Thy Father." Williams plays Leroy Jethro Moore, a close friend of Gibbs' father — so close, in fact, that Gibbs' full name is actually Leroy Jethro Gibbs.

Williams pawns off his Medal of Honor, which leads Gibbs on a quest to discover why Moore and his father had a falling out. He is eventually able to patch things up between the two, and Williams goes on to make a second appearance on the show at Gibbs' father's funeral.

Producer Mark Horowitz had this to say about working with Williams: "We had all this history built into this story, so you really needed somebody who needed to have a certain amount of gravitas. Billy brought a tremendous amount of charm and grace to that part. He had an ease about him. Just a lovely man to work with. He was the perfect person for that role." The fans agree.

Danica McKellar has had an interesting career as an actor. The role she is most known for was one of her very first, as Gwendolyn "Winnie" Cooper on The Wonder Years. Since then, she has appeared in How I Met Your Mother, The West Wing, and a wide variety of animated work, in addition to her career in mathematics. 

McKellar appears in the season two episode "Witness." She is actually the character who the title refers to: Erin Kendall, a graduate student who records and reports a murder to the NCIS. Unfortunately for her, the killer then sets their sights on her and... well, let's just say the NCIS has a new case to investigate before the episode is over. Though McKellar fans must mourn her character's fate, as it means she'll likely never return to NCIS, they have much other work to content themselves with. And it doesn't all require an understanding of "ferromagnetic Ashkin-Teller models," either!

This one is exceptionally fun, because Jesse Plemons (who is not Matt Damon, despite how many times we've seen him in something and asked "Wait... is that Matt Damon?") actually appears in the same episode as another person on this same list. Plemons plays Jason Geckler in the third season episode "Deception," which also boasts Zac Efron's NCIS appearance.

In the episode, two high school students are brought in for questioning about a cell phone linked to a kidnapping. Those students, one of whom is played by Zac Efron, eventually let slip that they got the phone from another student named Jason Geckler. Geckler is brought in, and he is played by none other than Jesse Plemons.

Neither Efron nor Plemons' character actually commits the crime being investigated by the team, though they are both very uncooperative with the NCIS. However, they both eventually give the team enough information to find what they are after. 

Jaleel White pulled off a tremendous trick with his most famous character. One might think playing Steve Urkel in Family Matters might doom him to typecasting forever — but in fact, Urkel is such a ridiculous caricature that White is able to easily distance himself from the role. When he isn't screaming in suspenders and giant glasses, you don't peg him as Urkel. It's no surprise, then, that he's gone on to have a vast and varied career.

Take season nine episode "A Desperate Man." Jaleel White plays a small but pivotal role in the episode, but you would barely know it's him unless you regularly track White's post-Family Matters acting career. It's a very understated role as well, allowing White to show off his acting chops against the impressive ensemble cast that makes up NCIS. The episode itself is pretty standard NCIS fare, with the team having to sift through multiple witnesses to find out who is trustworthy and who isn't. Of course, by the end, the team has solved the mystery — and White's been given a chance to shine.

Jamie Lee Curtis is one of the bigger stars to appear on NCIS. Her turn on the show is, appropriately, memorable — she has a multi-episode arc over the course of the show's ninth season, encompassing five different episodes. She plays Samantha Ryan, a doctor in Psychological Operations with the Department of Defense, who is brought in on a case the NCIS is working on.

Ryan gets into a relationship with Gibbs over the course of Curtis' brief run on the show, but her last appearance comes in the season nine finale "Till Death Do Us Part." Her character was not killed off, though, so there could still be a chance for Curtis to make another appearance on NCIS.

Curtis, funnily enough, had already co-starred before with Gibbs actor Mark Harmon — the two appear together in 2003's Freaky Friday. Curtis has said before how fond she is of working with Harmon. Could a Ryan reappearance ever come to pass? Fans can only hope.

Eric Stonestreet is best known for his comedic acting, as showcased in his role as Cameron Tucker on Modern Family (and as Kansas City Chiefs coach Andy Reid's brother, Randy, an avid jet ski salesman). It would be easy, then, to dismiss his NCIS character, Harvey Ames, as a bit of rent-a-cop comic relief. It would also be wrong. Ames, who appears in the season six Christmas episode "Silent Night," is much more than he appears to be.

Ames first shows up as the team is investigating a case, flirting with Ziva and suggesting that maybe he'd be a good fit to join the NCIS. He is basically shooed away and dismissed, but he returns at the end of the episode when it is revealed that he is responsible for the murder the team is investigating. Upon being exposed, he pulls a taser, shoots McGee with it, and attempts to flee. He is apprehended by Gibbs, and confesses to his part in the case.

It's always great when a child actor can go toe-to-toe with experienced actors, and that's exactly what you get when you sit down to watch season twelve's "Parental Guidance Suggested." Its featured child actor is none other than Millie Bobby Brown in one of her first appearances. She was only ten years old when the episode first aired, but she has no problem holding her own alongside the NCIS ensemble.

Brown plays a girl named Rachel who witnesses her mother's murder. Her father is a Navy commander and regularly travels, but he is forced to return home to stay with Rachel after this event. The team investigates and much of the evidence seems to point at Rachel's father being the culprit. A few things don't add up, however, and it is eventually revealed that Rachel herself murdered her mother so that her father would be forced to stop traveling.

Brown brings the intensity to the role that she is known for — it's easy to forget how young she is when she starts talking about how much she hated her mother. No wonder Brown would prove to be so good at portraying Stranger Things' Eleven, another bundle of trauma and zeal.