George R.R. Martin
Author and co-executive producer George R.R. Martin arrives for the premiere of the fourth season of HBO series "Game of Thrones" in New York March 18, 2014. REUTERS/Lucas Jackson Reuters/Lucas Jackson

To be played by Toby Sebastian for "Game of Thrones" season 5, Trystane Martell is the one of the new characters in the upcoming season of HBO's epic fantasy series. Promised to Myrcella Baratheon, daughter of King Robert Baratheon, the young prince is the son of the ruling prince of Dorne, Doran Martell and his wife, Mellario of Norvos.

Sebastian's latest casting was announced during the recent San Diego Comic Con together with eight other characters including the infamous Sand Snakes, Red Viper's illegitimate daughters, and Hollywood actor Jonathan Pryce to play High Sparrow. Hailed from Oxford, England, the young actor started his career in entertainment as a singer/songwriter and made his feature debut in "After The Dark" and "Barely Lethal" acting alongside "Game of Thrones" Sophie Turner and Jessica Alba.

"Best surprise ever!!! Welcoming one of my favourite people to the Game Of Thrones cast @tobysebastian1 beyond excited," Turner wrote on her Instagram account after finding out that Toby was cast for GOT's season 5.

Here are the five things to know about Trystane Martell.

1. The youngest son of Doran Martell, Trystane has two other siblings, Arianne Martell who is the heir of Sunspear and Quentyn Martell.

2. Married for love, his parents divorced after Mellario gave birth to Trystane because of cultural differences.

3. To prevent the Dornish kingdom from supporting Lannister enemies, Tyrion Lannister offered Myrcella to Doran Martell as the future wife of Trystane.

4. The prince has olive skin and straight black hair, and he is two years older than his future wife. Which make him 12-year-old when he was betrothed.

5. "Trystane and Myrcella get along well, often playing the game Cyvasse. Myrcella wins more than Trystane but Ser Arys Oakheart notes Trystane does not mind," according to Ice and Fire Wiki.

Meanwhile, renowned author of "A Song of Ice and Fire" George R.R. Martin recently revealed in a book festival that a few of the book fans know how the book is going to end. Thanks to his subtle hints, some clever fans have figured out the story behind the title and some speculations are pointing to Jon Snow and his part in restoring the peace in the Seven Kingdoms.