Mulder (David Duchovny) and Scully (Gillian Anderson) are going to try to save the world in the finale of "The X-Files" miniseries. But first, the FBI partners will need some help from Tad O'Malley (Joel McHale), who hasn't been seen on the show since episode 1, "My Struggle.

In an interview with Entertainment Weekly, McHale said "all hell will break loose" in Monday's finale, titled "My Struggle II." He also said that the finale will tie together the miniseries and will be "the greatest of all time."

"There have been a lot of promises made over the last few episodes, and this will not disappoint," McHale teased.

McHale also joked that his character would die in the finale, but then added he wouldn't reveal if he lives or not on the show. However, he did say that if they do decide to do more shows in the future and they wanted him back, he'd be there "in a New York minute."

The X-Files Finale Joel McHale Scully (Gillian Anderson) will reunite with Tad O'Malley (Joel McHale) in the finale of "The X-Files" miniseries. Photo: Fox

O'Malley was last seen in episode 1, when he revealed to the world that humans had been using alien technology to experiment on people. His website was then shut down and his fate was left up in the air. O'Malley will return to the Internet in episode 6 with another revelation as Mulder and Scully try to stop an illness that's quickly spreading around the country.

Show creator Chris Carter told the International Business Times that fans can expect to see the finale end with a cliffhanger. He promised the episode will be a "big one" and that he's open to do future installments of the show. Whether that's another season or movie has not yet be revealed.

You can watch the promo video for the finale below:

"The X-Files" miniseries finale airs Monday, Feb. 22 on Fox at 8 p.m. EST.