5 Things to Know About the Music in 'Game of Thrones'

The beating drums, the clashing cymbals, the plaintive strings -- the memorable "Game of Thrones" theme song is already a classic.

The 'GoT' Season 3 opening sequence:

The percussive, propulsive score suits the action-heavy HBO drama. Composer Ramin Djawadi relies on the story and what he sees onscreen to guide his music.

"I read the scripts, but the visuals trigger a whole new level of inspiration," he told the Hollywood Reporter. "Like the main title -- they showed me this beautiful rough cut of the main title sequence. That really triggered me to write this theme."

Check out five things to know about the music of "Game of Thrones":

1. The "Game of Thrones" composer also scored "Iron Man."

Djawadi is the man behind the music of both "Game of Thrones" and the hugely popular first "Iron Man" movie. The scores share a rock sensibility; Djawadi uses a mix of orchestral and electronic sounds for "GoT."

[Related: The Story Behind the Surprise 'Downton Abbey' Cameo in 'Iron Man 3']

2. Some of the main characters have their own theme.

With the show's massive cast of characters, it would be impossible to write a specific theme for every single character. Important ones like Daenerys Targaryen have their own, though. Her theme has evolved from soft to soaring.

[Related: Miss the Last Episode of 'Thrones'? Catch Up With Our Recap]

"She's a good example of how when you look back to the first episode, when we planned her theme, it's not remotely as powerful as it is now," Djawadi told Yahoo! Music.

3. The producers like to rock.

For a few key scenes, David Benioff and D.B. Weiss approached rock bands to contribute songs. Last season, they asked the National to write the music for "Rains of Castamere," which was heard in the crucial "Blackwater" battle episode.

This season, they did the same thing with the Hold Steady for "The Bear and the Maiden Fair," with lyrics penned by series author George R.R. Martin. It played after the shocking moment when Jaime Lannister got his hand chopped off.

Watch the scene and hear the song:

"It's such a shocking ending, and when we read the scene in the books, it was so shocking to us," Weiss told Entertainment Weekly. "To really hammer home the shock of that moment you need something unexpected. There's no version of a traditional score that would keep you as off balance as we wanted that scene to leaving you feeling."

4. Fans have made many tribute versions of the opening score.

Imitation is the sincerest form of flattery, and Djawadi loves the fan renditions. "I love what people have done around the world with the theme," he said. "I love how creative people are."

The tributes include a heavy metal version, a cello trio, another featuring a mandolin, and one rendition done in a bell tower.

Watch the heavy metal cover:

5. The cast can sing the theme song.

At the Season 3 premiere in Los Angeles, cast members including Maisie Williams (Arya), Lena Headey (Cersei), and Isaac Hempstead-Wright (Bran) hummed the opening tune for MTV Geek.

"Little did you know that it's actually me on the recording, doing that -- beatboxing," joked John Bradley (Sam).

"Game of Thrones" airs Sundays at 9 PM on HBO.