George R.R. Martin
Co-executive producer George R.R. Martin arrives for the season premiere of HBO's "Game of Thrones" in San Francisco, California March 23, 2015. Reuters/Robert Galbraith

Josh Whitehouse as been cast in a lead role in the upcoming first “Game of Thrones” spin-off. The actor has been a part of the popular “Poldark” TV series. Meanwhile, “A Song of Ice and Fire” series author George RR Martin has confirmed the title of the new show to be “The Long Night.”

There are multiple new spin-off shows being developed by HBO, but the first one to be made has been written by Jane Goldman. According to a report by Deadline, Whitehouse will play the lead role on the show. Details about the character he is playing are currently being kept under wraps.

Whitehouse plays the role of Hugh Armitage in the popular “Poldark” TV series. Some of his other projects include “Valley Girl,” “Alleycats,” and “The Receptionist.”

The other big casting announcement is Naomi Watts, who has been cast in yet another mystery role. The only detail about the character that has been announced was that she plays a character who is a charismatic socialite, hiding a dark secret.

Watts has been a part of projects like the 2005 flick “King Kong,” “Mulholland Drive,” and “The Impossible.” More casting announcements are expected in the coming weeks, as the work for the show continues in full swing.

In his recent blog post, Martin confirmed that the casting is now underway for the show. He also confirmed in the post the title of the new spin-off series. “The Long Night” is now the confirmed title, a name that Martin previously suggested would be selected, but they may add the words “Game of Thrones” for branding purposes, to make it easier for the fans to recognise the show as a spin-off.

With the production yet to start, the spin-off may only arrive by 2020. Meanwhile, the last season of “Game of Thrones” is set to premiere some time in 2019.