Question: Jason Momoa stars as Khal Drogo in a show based on a fantasy novel written by which author ?

Context paragraphs:
The Bad Batch: The Bad Batch is a 2016 American romantic drama horror-thriller film directed and written by Ana Lily Amirpour.  The film stars Suki Waterhouse, Jason Momoa, Giovanni Ribisi, Jim Carrey and Keanu Reeves.  Principal photography began on April 8, 2015 in Los Angeles.

Sugar Mountain (film): Sugar Mountain is an American thriller film directed by Richard Gray and written by Abe Pogos.  The film stars Cary Elwes, Jason Momoa, Drew Roy, Haley Webb, and Shane Coffey.  Filming began on March 10, 2014 in Seward, Alaska and ended on April 18.

Aquaman (film): Aquaman is an upcoming American superhero film based on the DC Comics character of the same name, distributed by Warner Bros.  Pictures.  It is intended to be the sixth installment in the DC Extended Universe (DCEU).  The film is being directed by James Wan, with a screenplay by Will Beall, from a story by Wan and Geoff Johns, and stars Jason Momoa, Amber Heard, Patrick Wilson, Willem Dafoe, Yahya Abdul-Mateen II, Temuera Morrison, Dolph Lundgren, and Nicole Kidman.

Bullet to the Head: Bullet to the Head is a 2012 American action thriller film directed by Walter Hill.  The screenplay by Alessandro Camon was based on the French graphic novel "Du Plomb Dans La Tête" written by Matz and illustrated by Colin Wilson.  The film stars Sylvester Stallone, Sung Kang, Sarah Shahi, Adewale Akinnuoye-Agbaje, Christian Slater, and Jason Momoa.  Alexandra Milchan, Alfred Gough, Miles Millar, and Kevin King-Templeton produced the film.  The movie follows a hitman and a cop who are forced to work together to bring down a corrupt businessman and mafia boss after they are targeted by the latter's associates.

Khal Drogo: Khal Drogo is a fictional character in the "A Song of Ice and Fire" series of fantasy novels by American author George R. R. Martin, and its television adaptation "Game of Thrones".

Jason Momoa: Joseph Jason Namakaeha Momoa (born August 1, 1979) is an American actor, model, director, writer, and producer.  He is known for his television roles as Ronon Dex on the military science fiction television series "Stargate Atlantis" (2004–2009) and as Khal Drogo in the HBO fantasy television series "Game of Thrones" (2011–2012).

Braven: Braven is an upcoming Canadian action thriller film directed by Lin Oeding and written by Mike Nilon and Thomas Pa'a Sibbett.  The film stars Jason Momoa, Garret Dillahunt, Stephen Lang, Jill Wagner, and Brendan Fletcher.  Principal photography began early-December 2015 in Newfoundland, Canada.

Stargate Atlantis (season 2): The second season of the television series "Stargate Atlantis" commenced airing on the Sci Fi Channel in the United States on July 15, 2005, concluded on The Movie Network in Canada on January 30, 2006, and contained 20 episodes.  The show itself is a spin off of its sister show, "Stargate SG-1".  The series was developed by Brad Wright and Robert C. Cooper, who also served as executive producers.  Season two regular cast members include Joe Flanigan, Torri Higginson, Jason Momoa, Rachel Luttrell, Paul McGillion, and David Hewlett as Dr. Rodney McKay.  The second season focuses on the Atlantis Expedition continuing to make the Wraith think that the city self-destructed, (The Siege Part III) while continuing to explore Pegasus and hunt for ZPMs (although they do have one now) this means at times lying to new allies about the city even sometimes claiming to be a small contingent that escaped the Siege; the season also marks the first time the Expedition is able to make contact with Earth although doing so uses a lot of power so the contact is oftentimes via the Daedalus, an intergalactic Earth-Asgard vessel commanded by Col. Steven Caldwell who makes clear his desire to be Military Leader of Atlantis but eventually settles for a sort of advisory role as it becomes clear that Dr. Weir and the Lt.Col Sheppard are a duo not to be messed with.  The central plot of the second season is the development of Dr. Beckett's retrovirus, which can, theoretically, turn a Wraith into a human.

Conan the Barbarian (2011 film): Conan the Barbarian is a 2011 American sword and sorcery film based on the character of the same name created by Robert E. Howard.  The film is a new interpretation of the "Conan" mythology, and is not related to the films featuring Arnold Schwarzenegger.  It stars Jason Momoa in the title role, alongside Rachel Nichols, Rose McGowan, Stephen Lang, Ron Perlman, and Bob Sapp with Marcus Nispel directing.

Once Upon a Time in Venice: Once Upon a Time in Venice is a 2017 American action comedy film directed and written by Mark and Robb Cullen in their directorial debuts.  The film stars Bruce Willis, Jason Momoa, John Goodman, Thomas Middleditch, Famke Janssen, and Adam Goldberg with supporting roles by Christopher McDonald, Stephanie Sigman, and Wood Harris.

Supporting paragraphs: Jason Momoa Khal Drogo
Answer: George R. R. Martin