Nico Parker and Mason Thomas will star in the live-action adaptation of 'How to Train Your Dragon'.

The 'Last of Us' actress will portray Astrid, while the 15-year-old 'Black Phone' actor will play fellow human rider Hiccup in the upcoming movie, The Hollywood Reporter has revealed.

According to the outlet, writer and director Dean DeBlois - who also helmed the original films - spent months looking for the right actors who would be able to grow into the roles in the way the characters grow into maturity throughout the series, which saw jumps in age across the three movies to highlight different stages of life.

Jay Baruchel and America Ferrera originally voiced Hiccup and Astrid in the animated trilogy.

The original 'How To Train Your Dragon' came to screens in 2010 and was a considerable success.

The movie introduced Hiccup, a misfit teenager who studies at a dragon-fighting school - and he tries to prove that he is a true Viking.

And news of a live-action adaptation based on the books by Cressida Cowell comes after DeBlois insisted the animated series would end at three movies.

In 2017, he confirmed that 'The Hidden World' would be the last to feature in the franchise as he and his team of writers believed they'd managed to draw the blockbuster to a close for good.

He said: "We thought about it for a long time and came up with what we think is a bittersweet way to say goodbye to these characters, but the right way. You will understand why Hiccup says, as you heard in the trailer, 'There were dragons when I was a boy.' And by the end of this film, you'll have answered the question [of] what could have happened to them."

Fans were left waiting for 'How To Train Your Dragon: The Hidden World' to drop since 2016 when bosses announced a 2017 release date before pushing it back to 2018 and then delaying it until 2019.

In 2015, DreamWorks Animation chief Jeffrey Katzenberg said the biggest issue with scheduling times was due to the restructuring of DreamWorks - the movie production company - and conceded that the three-films-a-year plan was very ambitious.