The Game of Thrones prequel series has tapped The Serpent star to play Ser Criston Cole, a member of King Viserys I Targaryen's Kingsguard, a knight whose bold actions helped pave the way to civil war. "He is the common-born son of the steward to the Lord of Blackhaven," George R.R. Martin wrote of Frankel's character on his blog. "He has no claim to lands or titles, all he has is his honor and his skill with sword and lance. He is a challenger, a champion, cheered by the commons, beloved of the ladies. He is a lover (or is he?), a seducer (or is he?), a betrayer (or is he?), a breaker of hearts and a maker of kings ... Welcome to Westeros, Fabien. And do keep that sword sharp." Martin noted that Frankel romanced Emilia Clarke in the movie Last Christmas. "And now he is getting tangled up with some more Targaryens," he wrote. "We shall see how that goes." ALSO: A "Winter is Coming" tweet from HBO's Game of Thrones Twitter account led to new calls to remake Season 8.