HBO has claimed the pair had withdrawn from the event because of "production and scheduling conflicts".
Maisie Williams (Ayra Stark), Jacob Anderson (Grey Worm), Isaac Hempstead Wright (Bran Stark), John Bradley (Samwell Tarly), Nikolaj Coster-Waldau (Jaime), Liam Cunningham (Davos Seaworth) and Conleth Hill (Lord Varys) will still attend.
There were other notable withdrawals from the same panel, with director Miguel Sapochnik, and actors Iain Glen (Jorah Mormont) and Nathalie Emmanuel (Missandei) all pulling out, with no reasons given so far.
Game of Thrones, despite the backlash from some fans, secured 32 Emmy nominations and in the process broke NYPD Blue's 1994 record of 26 nominations. The finale of the series drew 19.3 million viewers, which made HBO's highest-ever rated show and broke the network's record set the week before by The Bells, the penultimate episode which had 18.4 million viewers.