The actor, who has also starred in BBC miniseries Howards End and Little Women, has landed the role after a string of other stars were linked – including Harry Styles, who reportedly turned down the opportunity.
Hauer-King will star opposite Halle Bailey as Ariel, in an all-star cast which includes Melissa McCarthy as Ursula, Javier Bardem as King Triton and Daveed Diggs as Sebastien.
The film will be helmed by Chicago director Rob Marshall, who most recently achieved success with Mary Poppins Returns, while David Magee has penned the script.
Songs from the original will feature prominently in the remake, which will also include new material by Alan Menken and Lin Manual Miranda.
Production on The Little Mermaid – for which no release date has currently been scheduled – is expected to kick off at the beginning of 2020.
The Little Mermaid will be Hauer-King’s biggest film role to date – with his previous big-screen roles including The Last Photograph and Postcards from London.
It was also recently announced that World on Fire will return for a second season following the conclusion if its first run last weekend.