As if an unexpected pregnancy and the loss of her longtime partner weren't enough for Scully (Gillian Anderson) to contend with this season on The X-Files, Sunday's introduction of sexy sleuth Monica Reyes (played by Annabeth Gish) may finally push the perpetually put-upon G-woman over the edge.

"There is tension in the beginning because I am sort of the new girl on the block," Gish tells TV Guide Online. "But my character makes it very clear that I'm of no threat. I'm not coming in to try and take over [Scully's] division."

So, why is she invading Scully's heavily-trod turf? An expert in ritualistic crimes, Gish's alter ego is summoned by Agent Doggett (Robert Patrick) to help solve a case tied to the disappearance of Mulder (David Duchovny). And while the 31-year-old actress reveals that Reyes and Doggett do indeed have an existing relationship, the nature of their bond remains a question mark. "There is the suggestion of a romance," Gish teases. "But mainly we [once] worked on a case together involving the loss of his son, so bringing me in helps to illuminate his past as well."

The new agent's presence also promises to lighten things up on the notoriously dark and dour series. "[Reyes] is very warm and sunny... she has a spiritual perspective to her work and her life," explains Gish, who co-starred with Julia Roberts in 1988's Mystic Pizza. "I think they're just trying to breathe a little levity into the show with my character."

Gish signed on for four episodes and is slated to become a regular next season — should X-Files creator Chris Carter decide to continue on for a ninth year. "It's all up in the air," she offers. "Hopefully [it] will happen. I'm just having such a wonderful time, and it's a family I'd love to continue to work with."

That said, although speculation has it that Doggett and Reyes are being groomed as the next Mulder and Scully (Duchovny is not expected to stick around beyond this season and Anderson's contract expires in a year), Gish is too busy fulfilling her current commitment to ponder what the future might hold. "After 16 years of working in this business, this is the hardest thing I've ever done, just in terms of the hours and the amount of work and the way it consumes your life," she sighs of the X-Files grind. "It's like they make a little movie every week, 14- to 16-hour days are the norm, and it is quite grueling."