Filming for "Reign" season 4 is still well underway, and the cast members of the hit drama have been keeping fans up to date through social media.

Will Kemp, who was tapped to play the role of Mary's (Adelaide Kane) Lord Darnley, recently shared on Instagram a photo of his script for the eighth episode of the season.

It was revealed that the "Reign" season 4 episode in question is titled "Uncharted Waters." It does not reveal much about the plot, although it did reveal that Kemp's character will be around.

Kemp, like Adam Croasdell, who will play the role of Mary's third husband Bothwell, will only appear in four episodes. However, they were given the option to do more. It is unclear if the latter will be the case, although it does not look like Lord Darnley and Bothwell will be introduced immediately in the upcoming season.

Mary is still reeling from the death of her husband, Francis (Toby Regbo), and she is dealing with all sorts of issues being queen as well. Because of this, it is safe to say that the new characters will not arrive until after the first few episodes.

Kane and Kemp also shared photos and clips from behind the scenes. The latter shared a short video of the former reading "Modern Romance," a book by actor Aziz Ansari, and it looked like the two likes to have fun with the cast and crew in-between takes.

On what story to expect in "Reign" season 4, the new run will see Mary move on from Francis' death. This is where Lord Darnley and Bothwell — her second and third husband, respectively — enter the picture.

In real life, Lord Darnley was killed a year after he and Mary tied the knot. Bothwell then swooped in to try and win the queen's heart, which he successfully did. Interestingly, he is involved in a murder close to Mary's family. It is unknown if this will be depicted on the show.

"Reign" season 4 will premiere early next year on The CW. Rumor has it that it will be the show's swan song due to the declining ratings and viewership, although nothing has been confirmed yet.