Commuters cruising down Hollywood Boulevard on the evening of March 18 came across a familiar scene: red carpet rolled out, overhead lights bearing down on talent, photogs flashing bulbs, fans pouring over blockades across the street, hand-drawn signs waving back and forth, traffic snarled from lane closures.

Just another tentpole feature-film preem?

Guess again. The high-profile affair belonged to HBO’s “Game of Thrones,” the massive event a testament to the show’s exponential growth on the paybler since its 2011 debut. A long will-call line drifted down the street as showbiz members filled the Chinese Theater before the season three preem screening.

HBO’s Michael Lombardo took the stage to offer remarks, welcoming the crowd to the show’s first-ever preem and offering praise for “Game of Thrones” book series creator George R.R. Martin, who was embraced with thunderous applause.

Skein creators David Benioff and Daniel B. Weiss were introduced and offered their own retrospective on Martin.

“Seven years ago, Daniel and I met George R.R. Martin for the first time,” Benioff reflected. “And over a five-hour lunch, we tried to convince him to let us adapt his magnificent saga for television. Even though we’d never produced a television show before. Or a movie. Or an Internet short.”

Post-screening, guests crossed the street to pour into the Roosevelt afterparty, leaving cops tasked with guiding traffic at the whims of the crowd. Feather-adorned stilt walkers greeted guests who entered the expansive fete wondering which themed station they should visit first: manicures, air-brushed tattoos, archery or calligraphy? Ben Silverman ducked under a stilt walker in a dash upstairs as “Game of Thrones” thesps mingled and grubbed with “True Blood” cast members, blowing dry ice smoke through their noses at the Dragon’s Breath station. Jay Roach relaxed nearby, taking in the stage show of musicians, sword fighters and jugglers.

At the calligraphy station tucked away in a separate room, hired artists — along with the rest of the party staff — spoke to guests in a “Game of Thrones” accent. When someone asked for a profane word done in calligraphy, the artist accommodated. But, afterwards, another member from the station leaned in and, breaking character with an Angeleno accent, whispered, “You should have Instagrammed that.”