It's a whole new ballgame on "Game of Thrones."

The eighth and final season will push all of them into new territory, as John Bradley (Sam Tarly) told TV Guide. And it will push the actors to explore new depths.

"These characters are so detailed and so rich, you can feel that you've got a pretty good handle on your character," he said. "You can predict how your character will react in any given circumstance, but when you place these characters in a new environment, it's always putting them under a microscope, and you constantly have to reexamine your character."

He added, "Each of the characters this year is placed in a completely alien environment at some point in the season that they've never been placed in before. The thrill is seeing how they react to it and how they respond... This season, I think, more than any other is stretching these characters."

Season 7 already shifted many of the characters around. Daenerys finally reached Westeros and flew north of the Wall; Jon sailed to Dragonstone and met (and bedded) the Targaryen queen; Cersei saw a White Walker firsthand; and the Stark children reunited for the first time since Season 1.

Bradley acknowledged that the final season will have even more to do to wrap up the story.

"We are kind of feeling the pressure to get it right because we want to satisfy people," he said. "We want to give people a payoff that they're going to be happy with."

"Game of Thrones" Season 8 is expected to debut in 2019.