James “J.J.” Murphy (May 7, 1928 – August 8, 2014) was a Northern Irish actor.
He was cast in the role of Ser Denys Mallister, a member of the Night's Watch. Murphy died just four days after completing his first scenes for Game of Thrones. According to his agent Phillip Young, Murphy was “absolutely delighted”, to be cast “in one of the biggest productions in the world at this stage in his career.”
Co-creators David Benioff and D.B. Weiss made an official statement via HBO's Twitter account that the role will not be recast: "We will not be recasting J.J. Murphy. He was a lovely man, and the best Denys Mallister we could have hoped for. And now his watch is ended."
Apparently Season 5 will continue to use those scenes that Murphy already filmed, and possibly rewrite other scenes to work around his absence.