The actor gave a glimpse into Friday's pivotal episode and what it could mean for the future in the THR Cover Lounge.

Some new blood is coming into the mix on Fringe.

Henry Ian Cusick and Georgina Haig make their debut on Friday's episode of the Fox sci-fi drama, and, as star John Noble told The Hollywood Reporter when he dropped by the THR Cover Lounge, "It's a real game-changer."

Noble echoed co-star Josh Jackson's sentiments that the 19th episode is a glimpse of what's to come should a fifth season be ordered. "It would also be an indicator of where we may go in the future should we go there," Noble shared.

The latter episodes of any given season have been key since Fringe began in 2008. Last season, episode 19 saw the Fringe team in animated form (with a special cameo by Leonard Nimoy) and in season 2, the series went the musical route with its 20th hour.

Noble delved deeper into what the episode, set in 2036, means for the multiple universes.

"The main question when you look at 19 is what on earth caused them to do what they did, so that they could be transported into this place. For example, Walter isn't any older," Noble teased. "Something has happened to bring them forward but remnants of their past life in terms of the effects they've had on people are brought forward."

"For the first time, we will have a common enemy," he added, "where we will have to fight tooth and nail for our own survival."

Fringe airs Fridays at 9 p.m. on Fox.