As I mentioned in my last list of 10 people you didn't know were in the X-Files, there really were a lot of famous faces in this series. Here are a further 10 people you probably didn't know were ever in The X-Files...
Kathy appeared in Fight Club (season 7, episode 20) of The X-Files as both Betty Templeton and Lulu Pfeiffer - doppelgangers who wreaked havok whenever they were in the same place at the same time.
Okay, so Jodie Foster wasn't actually in the episode, but she provided the voice for Betty, a jealous tattoo, in Never Again (season 4 episode 13).
I love love love Lily Tomlin. It's the only appropriate reaction, I think. (Please no-one tell me if she's renowned for kicking kittens or anything.) Lily was in How The Ghosts Stole Christmas (season 6 episode 6).
This Lili appeared in Mind's Eye (season 5 episode 16) as a blind woman who 'sees' a violent crime, and ends up accused of having committed it herself.
Brad Dourif showed up to play the magnificently named Luther Lee Boggs in Beyond The Sea (season 1 episode 13), a man who claims to be able to communicate with Scully's dead father. Oddly, this episode sees Scully believing while Mulder doesn't. Yay for role reversal!
The last part of this list has a horror movie theme running through it. Tony Todd, the Candyman himself, shows up in Sleepless (season 2 episode 4) as Augustus Cole, a man who hasn't slept for over 20 years as a result of a government experiment. This episode is probably better remembered for featuring Krycek for the first time, but - dude, it's the Candyman!
The man with the chin himself turns up in Terms of Endearment (season 6 episode 7). He plays Wayne Weinsider, a demon who is trying to have a demon child and kills all human offspring he has with women - until he encounters a demon woman. Only she's trying to have a human child and kills the demon ones. Or the other way around. Clearly, I thought I could remember this episode better than I really can; I mostly just remember the line "What are you doing, Wayne?"
The Saw franchise's increasingly decrepit bad guy Jigsaw popped up in Brand X (season 7 episode 18), an anti-smoking episode that featured deadly cigarettes. Bell isn't the only Saw cast member to have been in The X-Files, either...
... Jigsaw's accomplice Amanda, or Shawnee Smith if you're a member of the reality-based community, was in Firewalker (season 2 episode 9). And...
... Cary Elwes was in 6 episodes of season 9. So it's likely you knew that he was in The X-Files, but given the Saw connection I couldn't quite bring myself to leave him off the list.
Go on, then. Who did I miss?