Maisie Williams

Writer and director Josh Boone set his sights on her last year but could only confirm the casting when the movie was green-lit this year.

New Mutants will focus on the "angst-driven" adventures of a group of teenage mutants.

Anya Taylor-Joy, whose credits include The Witch and Split, will also star in the film, which is due out next year.

The first script from the HBO drama's upcoming Season 7 was apparently so intense, the star couldn't contain her emotions. And because this is 2016, she unleashed them all on Twitter.

"Just finished reading season 7," she wrote, "s--t gets REAL."

In the course of five tweets, the actress went on to make the wait for the new season even more unbearable for fans of the show.

"I'd start preparing yourselves now," she continued. "Scratch that, nothing will prepare you for this."