The X-Files is a series that began airing in 1993 and is a science fiction series that follows two FBI agents as they travel the country, investigating unusual events that seem to have a paranormal explanation. The series has remained a favorite for many people that like spooky, supernatural shows. But, even though it’s still so much fun to watch and re-watch our favorite episodes of the show, many fans may have missed some of the guest stars that appeared on the series throughout the years.

A lot of the actors and actresses that had guest roles on The X-Files have gone on to become major stars in Hollywood. Some of the actors and actresses that appeared on the show were already rising stars when their episode aired while others didn’t have their breakout role until sometime after, meaning that a lot of people totally forgot they were even on the show. To see 10 celebrities everyone totally forgot had guest spots on The X-Files, keep reading!

Lucy Liu

Before Lucy Liu was starring in Elementary or the 2000 remake of Charlie’s Angels, she appeared in a 1996 episode of The X-Files. She was in the episode “Hell Money” and played a character named Kim Hsin.

This episode was pretty terrifying. It followed as Mulder and Scully traveled to San Francisco’s Chinatown in order to investigate the murder of someone that was burned alive in a crematorium after having a number of their organs removed. Yikes! As it turns out, the murder has ties to a group that is running a dangerous lottery.

Ryan Reynolds

We may know him as Deadpool now, but how many people remember that Ryan Reynolds had a guest appearance in an episode of The X-Files? Back in 1996, 20 years before he took on the role of Wade Wilson, Ryan Reynolds appeared in the episode “Syzygy” of The X-Files as a high school athlete named Jay DeBoom.

In the episode, Mulder and Scully travel to investigate the deaths of several students that all went to the same high school. According to the people living in the town here the tragedies occurred, a Satanic cult is definitely guilty. As it turns out, the real cause of their deaths is more celestial than cultish.

Shia LaBeouf

Shia LaBeouf has been working in the acting world for quite some time. Although many people may think of the Disney Channel when they think about the early days of his career, serious fans will know that’s not all that he did. In 1999, he appeared in “The Goldberg Variation,” an episode of The X-Files, as a boy named Richie Lupone.

This episode wasn’t one that had a connection to the rest of the plot of the series and instead was focused on a single paranormal entity, something that the show did somewhat often. In this episode, Mulder and Scully investigate a man who truly may be the luckiest man alive, having been thrown out of a building and survived, and LaBeouf plays a young boy who lives in his apartment building.

Bryan Cranston

If the first show you think about when you hear Bryan Cranston’s name is Breaking Bad, you’re definitely not alone. That show has a lot of fans and Cranston’s performance as Walter White was incredible from beginning to end. But, he worked with the show’s creator, Vince Gilligan, another time, too. Back in 1998, he appeared in The X-Files episode “Drive.”

The episode follows a man who is plagued with a debilitating headache that can only be eased by one thing: driving as fast as he can. And if he stops driving? His head will explode. Literally. Mulder and Scully become entangled in the mystery when this man kidnaps Mulder and forces him to get behind the wheel.

Luke Wilson

Luke Wilson is the brother of Owen Wilson and has been in a number of movies and TV shows, including the early 2000s classic Legally Blonde. But three years before that movie came out, he appeared in the episode “Bad Blood” of The X-Files as Sheriff Hartwell.

This episode is a highly suspenseful one as it follows as Mulder and Scully tell their version of a series of events that lead to them driving a stake through the heart of a teenager. In their defense, they believed that he was a vampire and they were doing it to save the people in this Texas town.

Kevin Zegers

Kevin Zegers is best-known for appearing in movies like the Air Bud series now, but that’s not the only thing he was doing back in the 1990s. In 1995, he also had an appearance in an episode of The X-Files called “Revelations.” In the episode, he played a young boy named Kevin Kryder.

In the episode, Mulder and Scully are sent to investigate a popular evangelist who claims to be showing symptoms of stigmata - wounds in the same places as Christ had them on the cross. The evangelist was faking his wounds, but Mulder and Scully soon meet a young boy named Kevin who actually appears to be displaying symptoms of stigmata.

Cary Elwes

Although fans of Cary Elwes may think he’ll never top his performances in movies like The Princess Bride or Saw, those aren’t the only projects that he’s made an appearance in. Unlike many of the other celebrities on this list, Elwes actually had a recurring role on The X-Files and wasn’t simply the one-time subject of an investigation.

For nine episodes between 2001 and 2002, Cary Elwes played the role of Brad Follmer on the show. Follmer was the assistant director of the FBI for some time until some secrets about things that he had done outside of the office came to light.

Laurie Holden

Most people likely know Laurie Holden as Andrea from The Walking Dead. But, long before she was cozying up to The Governor, Laurie Holden was a recurring character on The X-Files.

On the series, she played the role of Marita Covarrubias. Following the death of X, an informant that was in contact with Mulder and Scully in order to aid their investigations, Marita was introduced as their new contact person. She appeared in a number of episodes between 1996 and 2000 and then returned one more time to appear in the original series finale in 2000.

Tony Shalhoub

Tony Shalhoub is an actor who became really well-known for his role on Monk. He’s played a variety of different roles since then, but one role that many people forget about is from before Monk even premiered. In 1995, he appeared in an episode of The X-Files called “Soft Light” as Dr. Chester Ray Banton.

In the episode, Mulder and Scully are tasked with investigating a mysterious series of disappearances that seem to be tied to a scientist with some truly unusual abilities.

Kathy Griffin

Kathy Griffin is an actress and stand-up comedian that has become quite a controversial figure in Hollywood over the years. But, before she was known for some of her more outlandish stunts, she appeared on an episode of The X-Files.

She appeared in the 2000 episode “Fight Club” as two different roles: Betty Templeton and Lulu Pfeiffer. Betty and Lulu are a pair of doppelgängers that don’t know anything about each other. But, whenever they come together, people around them become inexplicably violent toward one another. Could Betty and Lulu be causing this? Mulder and Scully set out to find out.

Next: 10 Best X-Files Episodes (According to IMDb)