The 46-year-old actress confirmed she will reprise her role as Monica Reyes in a new season of the Fox revival starring David Duchovny and Gillian Anderson.
"Shall we? #iwanttobelieve #monicareyes #xfiles," she wrote Sunday on Instagram.
Gish followed up by posting a throwback photo on Duchovny's 57th birthday Monday and a picture with stuntwoman Melissa Stubs on the show's set Tuesday in Vancouver, B.C.
"Love working with @actiongirl99 again in Van! #xfiles," she captioned the snapshot.
Gish originally played Monica in Seasons 8 and 9 of "The X-Files," and returned for Season 10 after Fox revived the series.
Fox Entertainment president David Madden teased Season 11 at the Television Critics Association summer press tour Tuesday.
"The first episode will be a mythology episode," Madden said of the new season, according to IGN. "Then there will be eight standalone episodes, and [end with another mythology episode]."
"You will see the Cigarette Smoking Man. You may even see, maybe, some tip to the Lone Gunmen along the line," he added. "There will be other characters from the previous mythology that will be reprised."
"The X-Files" will return for an 11th season during the 2017-2018 television season.
Gish is also known for playing Charlotte Millwright on "The Bridge," Sheriff Althea Jarry on "Sons of Anarchy" and Diane Gould on "Halt and Catch Fire."
Copyright 2017 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent.