Question: Hafþór Júlíus "Thor" Björnsson, is an Icelandic professional strongman, actor, and former professional basketball player, he plays which 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"?
Sentence (from "Catelyn Stark"): She is a prominent point of view character in the novels.
Relevant evidence: No