https://www.cnet.com/news/game-of-thrones-conquers-own-viewer-record-with-the-long-night/

That number tops the previous record of 17.4 million who tuned in for the season 8 premiere. Compare that with 16.9 million watchers for the season 7 finale. 

The overnight numbers are just the beginning. This season will likely surpass the 33 million-per-episode average from the previous season, according to Quentin Schaffer, executive vice president of corporate communications for HBO.