According to The Hollywood Reporter, the Northern Ireland director has previously directed episodes of Showtime's Dexter and Brotherhood.
Game of Thrones was originally expected to debut in the spring of next year, but start of production was pushed back to July 26. It's unclear if the new start date on the series will impact its premiere plans. The production has also added actress Emilia Clarke to the cast.
CLICK HERE to watch the first promo for HBO's ten-episode fantasy series.