Television's most famous dragons Drogon, Rhaegal, and Viserion are set to return on the silver screen in a few days.

Now, fans of the fire-breathing trio may want to keep an ear out for their bone-shattering roars.

Mating Sounds Inspire Drogon's Loving Purrs To Danaerys

Giant tortoises are far from the first creature that comes to mind when Daenerys Targaryen's "dragon children" appear on HBO's Game of Thrones, much less, giant tortoises having sex. These animals make extremely distinct sounds during mating and anyone who wants to hear it can simply tune in to HBO.

The mating sounds of giant tortoises are actually one of the biggest influences of the noises the dragons make on the show, according to the show's sound designer Paula Fairfield.

During an interview on Radiolab's Big Little Questions podcast in 2017, Fairfield revealed that Drogon's purring in the proximity of Danaerys are inspired by the groans that male giant tortoises emit in the process of mating.

"The groan of the male actually became, with some work and adjustments, the source for Drogon's purr with [Daenerys]," Fairfield said in the podcast. "The funny thing about the purr with Drogon was watching people watching [the show] and giggling when they heard it, but not really knowing why. To me, it's because it had that essence, that kind of sensual, sexual essence."

There are also slight variations in the different dragon sounds, which the Game of Thrones team based on the distinct personalities of the creatures.

"I have sounds I might choose based on the certain personality types I might want to push forward," she continued. "So, in the case of Drogon, she named that dragon after Khal Drago, her hot, late husband. So Drogon is like her lover."

It's why Drogon makes softer, more dulcet sounds. Unlike the two other dragons, Danaerys' favorite whistles at her constantly.

Game of Thrones Dragons Season 8

Every season has shown more and more complex scenes with the dragons and the show's final season is expected to take these scenes another level higher.

Film School Rejects notes that Game of Thrones Season 8 will feature two dragons dueling against each other in the sky for the first time. After all, Viserion is now part of the Night King's undead army and he will likely rise up against his brothers within the next eight episodes.

Game of Thrones Season 8 begins airing on Sunday, April 14.