The eighth and final season of "Game of Thrones" may not air until 2019, but that does not mean fans no longer have reason to rejoice. In fact, a fifth prequel to the popular fantasy series is said to be in the works at HBO.

According to Entertainment Weekly, a fifth "Game of Thrones" prequel series is being developed by screenwriter Bryan Cogman with the supervision of "A Song of Ice and Fire" author George R.R. Martin. Unfortunately, plot details are being kept under wraps for now.

Cogman is known for writing 10 episodes of "Game of Thrones" - "Cripples, Bastards, and Broken Things," "What Is Dead May Never Die," "Kissed by Fire," "Oathkeeper," "The Laws of Gods and Men," "Kill the Boy," "Unbowed, Unbent, Unbroken," "Blood of My Blood," "The Broken Man," and "Stormborn." Also, he has not been secretive about his love for Martin's works.

"I immediately fell in love with the book from page one, as most people do," Cogman said in a 2011 interview with The Westeros.org. "It's probably the most fun I've ever had reading anything. It's inspired storytelling, that's all there is to it, and the characters are so rich, the themes are so varied. I love it."

The prequel news should come as no surprise to "Game of Thrones" fans. It was in May when HBO commissioned five screenwriters – including Carly Wray ("Mad Men" and "The Leftovers"), Jane Goldman ("Kingsman: The Golden Circle"), Brian Helgeland ("Legend") and Max Borenstein ("Kong: Skull Island") - to develop different spin-offs series.

"None of these new shows will be spinning off from 'Game of Thrones' in the traditional sense," Martin wrote on his blog at the time. "Every one of the concepts under discussion is a prequel, rather than a sequel. Some may not even be set on Westeros."