'Outlander' season 2 spoilers, news: Series gets double season renewal; Sam Heughan teases twists in season finale

Starz has renewed its Golden Globe-nominated series "Outlander" for seasons 3 and 4.

The popular historical romance/drama, which stars Caitriona Balfe as time-traveling nurse Claire Randall and Sam Heughan as Highland warrior Jamie Fraser, is based on the "Outlander" series of novels by bestselling author Diana Gabaldon. The show's first season was based on Gabaldon's "Outlander," the first novel in the series. The second season, which is currently approaching its finale, is based on "Dragonfly in Amber," the second installment.

The third season of "Outlander" will be based on Gabaldon's "Voyager," while the fourth season will adapt the author's "Drums of Autumn."

There are eight books in the "Outlander" series. The eighth, "Written in My Own Heart's Blood," was published in 2014.

"'Outlander' is like nothing seen before on television," Starz CEO Chris Albrecht said of the double season renewal, as quoted by Variety. "...[W]e are thrilled and honored to be able to continue the story that began with author Diana Gabaldon, and is brought to life by the incredibly talented Ronald D. Moore."

Meanwhile, it seems like the upcoming season 2 finale of "Outlander" will feature some twists that will surprise even the most avid fans of the Gabaldon books.

While the series currently has Claire and Jamie attempting to alter the fate of the Highlanders, the series has already shown that the two are poised to fail. In the opening scene of the second season, Claire was back in the 20th century and was finding out that the British had won the Battle of Culloden.

"Outlander" fans also already know that Claire will be launched back into the future and that her departure will be a heartbreaking one.

Nevertheless, "Outlander" star Sam Heughan says that just because the battle's outcome can't be changed doesn't mean that the season finale will be perfectly predictable.

"Ultimately the show has always been about relationships," he told IGN. "Not only is that the climax of history, but it's also the climax of the relationships that are happening at the time. It's all doomed, and we can't stop history from happening.

"[Season 2] certainly has a climax," he added. "[Showrunner Ron Moore] has also got some surprises."

"Outlander" airs Saturdays at 10 p.m. ET on Starz.