HBO said Sunday's broadcast audience, including on its HBO GO and HBO NOW apps, exceeded the previous series high of 16.9 million viewers for the Season 7 finale in 2017.
On social media, Sunday's premiere was also the most-tweeted-about episode of the show ever, with more than 5 million Tweets, and 11 million mentions throughout the course of the weekend, HBO said in a statement.
All of the top 10 global Twitter trends late Sunday evening were about the episode.
The series set among warring families in the fictional kingdom of Westeros, which began in 2007, has become HBO's biggest hit. Season 7 averaged 32.8 million viewers per episode when delayed viewing was counted.
"Game of Thrones" is available in over 150 countries worldwide, but HBO said viewing data is not easily retrieved in many of those markets, making a global figure impossible to calculate.
According to Ynet, there were 6,333,279 eligible voters during the 2019, April 9th election.