Narrowing down our shortlist of a hundred names to these ten has been a feat worthy of mystical investigation itself, and has meant no-shows for some big names (Brad Dourif, Jack Black, Seth Green, Kathy Griffin, Shia LaBeouf, Ryan Reynolds, Bruce Campbell and Martin Landau) and some less big ones (Garrett Dillahunt, CCH Pounder, Deep Roy, Veronica Cartwright and Penny Johnson).
Our first entry highlights immediately the main problem with selecting guest appearances on The X Files, episodes in which a few cult names appear together.
Huffman is a guest star on Season 1’s Ice (frequently – and reasonably – thought of as a retread of John Carpenter’s The Thing), an episode which also features genre favourites Xander Berkeley (24) and Joff Kober (Buffy). Huffman wins, though, partly for her Desperate Housewives credentials and partly for a stunning turn in Transamerica.
Xena herself showed up late in the life of The X Files, a period of the show which is not widely loved, so many are not aware of her turn in the two-part Nothing Important Happened Today as an alien/human hybrid Supersoldier (a storyline which also featured a pre-Firefly Adam Baldwin).
Admittedly, watching Lucy beat people up on TV is a bit obvious, but she does it so well.
Improbable sees Burt plays Mr Burt, an individual who might or might not be (but probably is) God, and exerts a curious influence on the world and people around him.
It’s one of the series’ most bizarre moments and divides fans to this day.
Candyman star Todd is a bit of a genre heavyweight and his appearance in the episode Sleepless is another fine notch on his cult belt.
As Augustus “Preacher” Cole, he had his capacity for sleep removed during the Vietnam War as an experiment to create the ultimate soldier, but years of sleeplessness have taken their toll, and now so will he…
Better known, of course, as John Locke in Lost, O’Quinn played three different characters (Lt Tilman in Aubrey, Darius Michaud in the first movie and the Shadow Man in the last throes of the series).
The actor also made regular appearances in sister series Millennium.
Firefly star Jewel was already an established child actress before appearing, aged 13, in the profoundly upsetting episode Oubliette as a kidnapped child who engenders psychic empathy in a former victim and, in Fox Mulder, memories of his own abducted sister.
A superb, but dark episode.
Granddaughter of Bing Crosby, Denise holds a special place in genre fandom due to having played a lead Star Trek character: Tasha Yar in The Next Generation. Though her time on the series was brief, she did make a return appearance both as Yar and as her half-Romulan daughter.
The X Files saw her playing Dr Mary Speake, Scully’s obstetrician in Empedocles and Essence.
The Saw franchise has shared a number of actors with The X Files: Shawnee Smith, Cary Elwes and Michael Emerson for starters, but it’s the big man, Jigsaw himself, who struck the most impressive figure.
As Darryl Weaver in the episode Brand X, he’s a character who wants you to know smoking is bad for you, especially if you smoke tobacco with beetle eggs in it.
Now, was this name a surprise or not? We’re often amazed at the number of people who forget that Jodie Foster was in an episode of The X Files.
Mind you, since she played the voice of what can only be described as an evil tattoo, in Never Again, we can probably understand that.
Two years before he hit big playing Hal in Malcolm in the Middle, Cranston played Patrick Crump in Drive (not to be confused with the film of the same name, in which the actor also appears), essentially a shameless (though excellent) Speed knockoff about an unsympathetic man who has to continue moving in a certain direction at a certain speed or face dire consequences.
Episode writer Vince Gilligan was so happy with Cranston’s performance that he later selected the actor to be the lead in his series Breaking Bad.
Who’s your favourite ever guest star in The X Files? Let us know below…