Perhaps you know them from elsewhere...
Movies, music or other TV shows.
But these actors made quite an impression with nothing more than a guest role.
Some of them did it over a several installments while others had just one episode to make their mark.
Either way, we found their performances not only memorable but unforgettable.
From dramas to comedies to sci-fi...
Check out these 13 guest stars who left their mark on some our favorite current shows on TV.
James Marsters and Charisma Carpenter - Supernatural
James Marsters and Charisma Carpenter appeared on Supernatural as a bickering married couple. They were also powerful witches and were using their magic against each other. Dean and Sam stepped in to stop it but in the end, it was their love that ended the feud. Seeing Buffy the Vampire Slayer alums together is always fun! They didn't interact all that much on Buffy (with Cordeilia going over to Angel) but they did some pretty heavy interacting on Supernatural (if you know what I mean!)
Paul Reubens - Gotham
Who doesn't love Pee-wee Herman? Though not as wacky as his iconic man/boy character, Paul Reubens' stint as Elijah Van Dahl was just the kind of quirky you'd expect Penguin's dad to be. It's just too bad we were only able to enjoy Reubens for two short episodes.
Cyndi Lauper - Bones
Cyndi Lauper has guest starred on Bones four times as psychic Avalan Harmonia…and isn't that just the perfect name! Lauper's Avalan plays perfectly next to Angela's open mindedness and even better opposite Brennan's strict science driven, evidence based philosophy. A psychic certainly wouldn't fit in regularly at the Jeffersonian but whenever Lauper pops in for a visit we know it’s going to be fun.
Megan Fox - New Girl
First, she was actually very funny. Second, she allowed the show to focus on the men of the loft instead of Jess, which is where the real humor lies. Third, she looked like Megan Fox!
Samuel L. Jackson - Marvel’s Agents of S.H.I.E.L.D.
S.H.I.E.L.D. had just fallen when Hydra's activated members took the organization down from within. Ward had just revealed he was Hydra and dropped FitzSimmons into the ocean. Everything was falling apart and all hope was lost until Nick Fury, the then director of the crumbling organization showed up to pull them out of the water. Let's face it, Samuel L. Jackson as Nick Fury will always be our hero.
Oliver Platt - The Good Wife
Oliver Platt joined The Good Wife for three episodes and they were awesome. Watching conservative billionaire Reese Dimple debate abortion and gay rights with liberal Diane Lockhart made for truly compelling TV. The discussion was as intelligent as it was riveting and Platt and Baranski’s performances were at the top of their game. Our only disappointment was that we didn't get to see more of R.D. before the series end.
Dana Delany - Castle
It was back on Castle Season 2 during the show's very first two-parter where fans first met Delaney's FBI Special Agent Jordan Shaw. Castle was fascinated, Beckett was jealous, and fans couldn't get enough. Not only would viewers love to see more of Jordan Shaw, we're fairly certain they'd happily watch her in her own spinoff.
Grey’s Anatomy - Christina Ricci
Way back on Grey's Anatomy Season 2, Christine Ricci played a paramedic who had to keep her hand on a bomb in order to keep it from exploding. The catch? The bomb was inside a patient's body! It was one of the more emotional guest spots of the series.
Nathan Lane - Modern Family
No one can make impending disaster look more fun than Nathan Lane. His character Pepper Saltzman pops up on Modern Family as one of Mitch and Cam's close friends. Pepper is an event planner but depending on the episode, we're not sure if we'd want him to plan our wedding or run in the other direction when we see him coming.
Michael Jackson - The Simpsons
Iconic singer Michael Jackson was such a huge fan of The Simpsons that he actually asked the creators if he could do a guest role. Although his name was never seen in the credits, he did give voice to mental patient Leon Kampowsky who just happened to have delusions about being none other than Michael Jackson.
Whoopi Goldberg - Blue Bloods
As much as we love Frank Reagan, he's never better than when he has to take on a worthy opponent who can make him look at an issue from a different perspective. That was Whoopi Goldberg's City Councilwoman Regina Thomas. Neither character truly won their argument but that just made us want to see Goldberg come back for round two.
Maisie Williams - Doctor Who
Much as she;s done with Arya Stark on Game of Thornes, Maisie channeled a fearlessness and strength into Ashildr on Doctor Who as the woman who could not die. We've begun to wonder if Williams is able to give a performance that is anything less than powerful.
Christine Baranski - The Big Bang Theory
Christine Baranski knows how to bring the mama drama to The Big Bang Theory. Beverly Hofstadter was never a warm and fuzzy type of mother and that affected Leonard in ways they're still dealing with today. As much fun as having Beverly finally go toe to toe with Sheldon’s mom (played by Laurie Metcalfe) is, it only makes us want her back for more.