(Rachel Orr/The Washington Post; Fox)

“The X Files” is filled with conspiracy theories. But there’s one integral mystery that fascinates, frustrates and thrills some fans like nothing else:

Are David Duchovny and Gillian Anderson dating in real life?

This is no ordinary version of the typical situation where people casually wonder if two co-stars are secretly in love even as the pair strenuously denies (as Duchovny and Anderson have) that there is a romance. For certain parts of “The X-Files” fandom, this question is a true enigma that has bubbled up over the years and now become a complete frenzy thanks to Fox’s “X-Files” reboot, which wraps up Monday night. As much as Duchovny and Anderson appear to despise constant questions about whether they’re together, they stoke the flames with photos like this:

Anything U want? Come get it at my XF auction to benefit NF & juvenile arthritis https://t.co/BlJ7iQxmkB Starts 1/24 pic.twitter.com/yq3AyYKrXU — Gillian Anderson (@GillianA) January 13, 2016

So, how did Duchovny and Anderson become so scrutinized to the point where there are entire blogs and Pinterest boards devoted to their every interaction? When the show originally aired from 1993 to 2002, some fans felt so strongly that paranormal investigators Fox Mulder (Duchovny) and Dana Scully (Anderson) should date that it’s believed to have coined the popular Internet phrase “shipping,” which means you root for two characters to end up together.

[‘The X Files’ revival has a chance of being horrible, but I don’t care]

Partly, this phenomenon exists because loyal TV fans simply have a personal investment in characters. Although in this case, the mystery is also the result of the unusual mystique surrounding Duchovny and Anderson’s on-set dynamic, which was famously rocky. They made no secret that after incredibly long days of filming, they didn’t get along.



Some ‘X-Files’ fans will intently analyze this type of body language between David Duchovny and Gillian Anderson. (Ed Araquel/FOX)

“Did David and I hate each other? At times yes like any brother and sister, husband and wife, co-worker and co-worker forced to spend that much time together under such strenuous circumstances,” Anderson once wrote. She referred to her working relationship with Duchovny as a “forced marriage.” Sometimes, she wouldn’t even answer the question about what she thought of her co-star.

Duchovny indicated he felt the same way. “We don’t run from trailer to trailer to exchange the news of the day. We have a successful working relationship and that’s the best way to go about this job,” he told Mr. Showbiz in 2000. Movieline asked if they had any relationship off-set: “Not really,” he said. “We’re friendly.”

The Internet is filled with similar quotes that have been dissected over time. See HitFix’s comprehensive timeline of their “feud,” including video of the time Anderson didn’t thank Duchovny in her 1997 Emmy speech when she won best actress in a drama.

Rather than deter “shippers,” this sort of tension can fuel their desire even more, as it shows that each one has intense feelings about the other. These fans also didn’t seem to mind that Anderson was married to her first husband until 1997, the same year that Duchovny tied the knot with actress Tea Leoni. Mulder and Scully’s situation was murky on the show as well: They had a baby together toward the end of the series, yet the writers never delved too much into their love life.

The theories about Duchovny and Anderson’s relationship gained steam over the years, as segments of “The X-Files” fandom scoured for clues. For instance, while Anderson didn’t thank Duchovny at the 1997 Emmys, before she walked up onstage, she kissed him before she kissed her boyfriend. And they took part in some steamy magazine photo shoots, like the Rolling Stone series of them in bed, or an Us Weekly cover where Anderson licked Duchovny’s face.

Mmm tastes good! Only one day left to bid on this round of items! https://t.co/vMg5KY2bHx pic.twitter.com/85sldbx3DQ — Gillian Anderson (@GillianA) February 20, 2016

Later, blooper reels from the 1998 “X-Files” movie showed them turning Scully and Mulder’s almost-kiss into an unscripted make-out session — although those cuts didn’t make the film.

A few years later, the conspiracy got a second wind when it was revealed that Duchovny and Anderson…were suddenly friends! Turns out having a break from filming healed old wounds. In an exhaustive timeline, a Tumblr user carefully documented many instances of the two interacting after the show ended. For example, in 2007, Anderson said she had a “very pleasant” lunch with Duchovny and tried to describe their dicey “X-Files” dynamic: “We were essentially married. We saw each other more than either of us saw our partners. And it was like any relationship — it had its ups and downs.”

At that point, the pair got along well enough to film a second “X-Files” movie in 2008. All hell really broke loose in 2013, when the two acted very flirty at events promoting the show’s 20th anniversary. (At this point, Duchovny had split from Leoni and Anderson was broken up with her longtime boyfriend.) At Comic-Con, Anderson even joked that the two of them had filmed a sex scene on “X-Files” that never made it to air — though eventually claimed she was just making it up. Immediately, rumors began that they were finally together. Or was it just to get publicity?

Another intensive Tumblr timeline detailed all of the instances of the two saying complimentary things to each other. The two started posing for Reddit AMA proof photos together in bed and frequently flirting on Twitter.

Raise your hand if you've ever felt personally victimized by David Duchovny and Gillian Anderson. pic.twitter.com/UXLfNTdBLn — Erin Ruberry (@erinruberry) January 23, 2016

Soon, Anderson sat for an infamous Huffington Post interview in March 2014 while promoting her NBC show “Crisis.” Anderson denied she and Duchovny were dating, though not very convincingly — and set the Internet on fire when she admitted, “There might even be more than an attraction, but it’s not going to happen.” A month later, she and Duchovny bantered on Twitter again (she called him “babe”) though he went on “The Tonight Show With Jimmy Fallon” to reiterate it was just a joke and, essentially, that people should relax.

Oh, there’s more: Word about Duchovny’s official divorce from Leoni leaked out on Aug. 9, 2014…Anderson’s birthday. To make things even more suspicious, Anderson had announced her split with her boyfriend two years prior…on Duchovny’s birthday. Coincidence?!

As you can imagine, this has only continued since news of “The X-Files” reboot surfaced and the two went on a very touchy-feely publicity tour. As usual, they’ve denied they’re involved. Still, they kissed onstage at a concert last year and recently appeared in a “Jimmy Kimmel Live” skit where they pretend to have sex on a desk. They also sat for a Jimmy Kimmel interview where they giggled, rubbed arms and Anderson had a laughing fit when Kimmel asked about their previous feud.

This type of behavior has fans wondering about them more than ever, and they’re frequently asked about their relationship. At the same time, Duchovny continues to be shocked to get the question, saying “There seems to be a certain kind of Twitter contingent that wants us to be together. It’s odd to me, because I’ve never had the fantasy of wanting two people together that aren’t, or are.” About two weeks ago, Anderson “crisply” asked, “Is that going to be the headline of this interview?” when a reporter deigned to ask whether the two have a romantic relationship. (Obviously, yes, it became the headline.)

Anderson’s reaction is ridiculous. As evidenced, their real “relationship,” true or false, has been a major part of the show’s story for two decades — and clearly they recognized it was excellent publicity for the show. So not only do Anderson and Duchovny appear to enjoy that it has become a big conspiracy, in the end, they perpetuate it more than anyone.

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