Let’s be real: beloved dramas are experts at making things new—except nothing throws the model for a loop like a shock guest appearance. Whether it’s a Hollywood icon stealing the scene in an interrogation cell or a surprise visit on a hospital floor, both NCIS and Chicago Med have created fans with indelible “did that just really happen?” moments. Take a trip back at 10 guest stars who didn’t just show up— they owned their episodes.
10. Zac Efron (NCIS, Season 3)
A pre-High School Musical teen, Zac Efron, made a blink-and-you-missed-it cameo on NCIS. The episode aired shortly before High School Musical launched him into fame, so the cameo feels like an under-the-radar Easter egg for sharp-eyed viewers. It’s the kind of nod you can boast about spotting.
9. Corbin Bleu (Chicago Med, Season 3, Episode 8)
Turns out that Efron was not the only High School Musical alum making her way into the franchise universe. Corbin Bleu guest-starred on Chicago Med as Tommy Oliver, a young guy who thought he had a small medical issue, but was diagnosed with life-changing news. Known for singing and dancing, Bleu proved that he could also deliver the drama.
8. Michelle Obama (NCIS, Season 13, Episode 13)
Talk star power—the First Lady herself showed up on the cast for a show that was taped at the White House. Playing herself, Michelle Obama took the opportunity to promote her Joining Forces initiative, which assisted military families. It was not a cameo—it was a moment of culture, making NCIS the first-ever drama produced within 1600 Pennsylvania Avenue.
7. Betty Buckley (Chicago Med, Season 2, Episode 5)
Broadway legend Betty Buckley stopped by Chicago Med with a heartbreaking turn as Olga Barlow, a woman struggling with poverty who resorted to eating pet food. What could have been played as odd or quirky turned into a gut-wrenching, unforgettable performance—exactly what you’d expect from a Tony winner.
6. Billy Dee Williams (NCIS, Season 10, Episode 5)
You can bet that when Billy Dee Williams shows up, it’s going to be something special. The Star Wars legend played Leroy Jethro Moore, the same man Gibbs was actually named after. His storyline had to do with tardy respect shown to veterans, but asking questions regarding race, loyalty, and friendship as well, all in a manner befitting an iconic Hollywood legend.
5. Malcolm McDowell (Chicago Med, Season 3, Episode 9)
Prestige casting in its finest form. Malcolm McDowell, who emerged with A Clockwork Orange, appeared as Dr. Marvin Jaffrey, a brilliant surgeon with a deadly prognosis. His exchanges with Dr. Ava Bekker were a study in pride, vulnerability, and gravitas, a reminder of why he is one of the finest working actors.
4. Jamie Lee Curtis (NCIS, Season 9)
Jamie Lee Curtis did not cameo—she inserted herself into Gibbs’ world. As Dr. Samantha Ryan, head of PsyOps, Curtis brought brains, wit, and surprise romance to the mix. Her multi-episode arc had fireworks bursting, and her dramatic exit had fans wishing her presence there longer.
3. Alexandra Grey (Chicago Med, Seasons 2 & 4)
Alexandra Grey’s Denise Lockwood was not a guest appearance—it was an emotional journey. As Maggie’s sister, she added some much-needed depth to topics such as gender transition, family acceptance, and internal struggle. Grey’s performance was interesting, nuanced, and one of the most buzzed-about storylines on the show.
2. Bob Newhart (NCIS, Season 8, Episode 12)
Comedy great Bob Newhart guest-starred as Dr. Walter Magnus, Ducky’s superior. At first, his deadpan was a welcome relief, but the episode took a dark turn when it was revealed that his character had Alzheimer’s. It was bittersweet, with classic Newhart timing and an emotional farewell.
1. Millie Bobby Brown (NCIS, Season 12)
It was only after Stranger Things catapulted her to stardom that teenager Millie Bobby Brown guest-starred on NCIS as Rachel, a child with a dirty little secret. Her chilling performance caught viewers’ attention—teasers that she would be one of the most talked-about young stars of Hollywood.
From new superstars to old timers, NCIS and Chicago Med guest spots have coaxed out some of the best in TV drama’s twisty moments. These cameos weren’t stunt casting — they added complexity, emotional resonance, and lasting moments that left viewers buzzing long after the credits rolled.