"The character breakdown described Gendry as tall and muscular with black hair. I was none of those three at the time. I thought, 'I could dye my hair and hit the gym, but I can't stretch my legs!'... My friend is such a big fan of the books that even he didn't actually approve of my casting as Gendry. But it was a nice little vote of confidence from David and Dan."
Joe Dempsie tweeted on the 17th June "Still rowin'...", to explain Gendry's absence in Season 4, referring to how he was last seen rowing back to King's Landing from Dragonstone. Following the absence of Gendry from the fourth, fifth and sixth seasons, Dempsie returned to the role for the seventh and eighth seasons.