The locs and hair extensions Halle wore in the movie cost over $150,000 and "took 12 to 14 hours" to install.
1. Halle Bailey was actually the first person to audition for Ariel, and director Rob Marshall said that he knew she was the perfect fit before she even came into the room.
2. Jonah Hauer-King's audition process to play Prince Eric lasted seven months. He sent in numerous self tapes of him playing Eric in different accents, sang several songs (including some from West Side Story, Rent, and ones written by Amy Winehouse), and went to an in-person screen test with Halle.
3. The locs and extensions that Halle wore in the movie cost over $150,000. The wrap process also "took 12 to 14 hours" which is a technique where they took the fake hair and wrapped it around Halle's natural hair, so she wouldn't have to color it or "change her internal hair structure."
4. Back in the '90s, one of Melissa McCarthy's first jobs was doing stand-up comedy in drag. She drew inspiration from her own experiences and other drag queens' performances (namely Divine) to portray Ursula.
5. One of the moments the remake recreates is Ariel's iconic hair flip moment. Halle said that it took about 20 tries to get the moment as close to perfect as possible.
6. In fact, part of Halle's, and several of the other mermaids', training included weight lifting to strengthen her necks.
7. Javier Bardem explained that he didn't even wear his merman tail much on set. The tails were worn to help him visualize his spacial awareness, but otherwise, he just wore pants while filming.
8. To film the "Under the Sea" scene, several dancers and puppeteers needed to wear blue screen suits and were then edited in post-production to appear as various sea creatures.