‘Game of Thrones’ season 5 premiere: How high could ratings go?

Where will Tyrion Lannister turn up in Sunday’s season 5 premiere of “Game of Thrones”?

Maybe the far-roaming dwarf played by Peter Dinklage will be counting all the viewers in what could well be a record-buster for HBO’s fantasy epic.

“GoT,” based on the books by George R.R. Martin, has been building its audience steadily since it premiered back in 2011 with just 2.2 million tuning in, according to Nielsen.

Last year’s season 4 opener was the biggest yet: 6.6 million viewers during the 9 p.m. initial airing. And the series kept building momentum: Episode 7 hit an all-time high of 7.2 million for the first run (a couple of other episodes last year tied that figure after rounding).

That means “Game of Thrones” is still a growth series, and season 5, which has been breathlessly promoted on talk shows and in the news media, could set a new benchmark. HBO says the show is already the most popular in its history, with 18.4 million total viewers across all platforms (including encore and DVR viewings). “The Sopranos” was the previous record holder, with 18.2 million.

Do the ratings for the initial run still matter? Well, HBO says no. Last year, the premium cable network -- part of a growing trend in the TV business -- stopped reporting overnight ratings, arguing that a single airing doesn’t provide a true snapshot of the audience’s size (the overnight figures are still collected by Nielsen but HBO no longer distributes them to the media). Instead, HBO waits to report numbers over the first full week of viewing and afterward.

Viewers can now watch shows like “Game of Thrones” through the new standalone service HBO Now, as well as through online platforms such as HBO Go. Add that to delayed viewing on DVRs, and you see why TV executives don’t like overnight ratings.

But the first night can still offer a good yardstick of whether a show’s appeal remains intact.

And in the case of “Game of Thrones,” it certainly seems to be. But we’ll know on Monday, just as we will probably know where Tyrion’s latest travels have taken him.

Twitter: @scottcollinsLAT