Freddie Stroma As Dickon Tarly In "Game Of Thrones", Replaced By Tom Hopper
The role of Dickon Tarly seems to have suited both of the actors portraying him very well. Knowing that it wouldn't be a recurring role, Freddie committed to Time After Time. Tom Hopper replaced him and admitted that the Dickon Tarly role secured him an acting job in the Umbrella Academy series.
Also, how would anyone be able to tell when some background character in GoT was replaced? There were a ton of them, and they all looked the same.