Not long ago, in an attempt to introduce my boyfriend to the brilliance that is The X-Files, I dug out some old VHS copies of episodes and showed him one of my favourite episodes. Part way through, one of the actors playing a bit part (the character committed suicide pretty early on) started to look familiar. Really, really familiar. Neither of us could quite place him for a long, long time.

Then, finally, it clicked. It was Ryan Reynolds. A very young Ryan Reynolds, but Ryan Reynolds nonetheless. Given that both I and my boyfriend are Reynolds fans (ever since Blade Trinity!) we were surprised we hadn’t known he’d ever been in The X-Files. But then, between one thing and another, there are a lot of people we either didn’t know or had forgotten showed up in The X-Files. So here are 10 famous actors whom you either didn’t know, or might have forgotten, were guest stars at one point or another…

Ryan ReynoldsReynolds plays Jay “Boom” DeBoom (I had to look that name up; it’s wonderfully improbable!) in Syzygy (season 3, episode 13). Rewatching this episode now, it’s not quite as mind-blowingly amazing as I remembered, but I still do love it silly amounts.

Seth Green Seth Green played Emil in the second episode of The X-Files, Deep Throat. I’m willing to bet that he’s the first person you thought of when you saw the title of this article; he seems to be one of the more known-about people you didn’t know about. (Um, pretend that made sense.)