A myriad of people recorded his message, uploading it to various social media platforms. Maisie Williams from "Game of Thrones" shared the video on her Instagram.
The Dolphin Project -- the nonprofit campaign that "aims to stop dolphin slaughter and exploitation around the world" (which Styles publicly supports) -- shared the video on Twitter, thanking old pal Styles for speaking up for animals who can't.
PETA also praised Styles for speaking out against SeaWorld and mentioned on its website plans to send him a "SeaWorld Kills" shirt and vegan chocolates shaped like dolphins. Of course, PETA also took to Twitter to share its view on the aquatic amusement park.
How has SeaWorld taken to the message? Not very well. In addition to sharing this public letter to Styles online, they're trying to set the record straight on Twitter, as well as all the good work they've done for the dolphin population.
In SeaWorld's letter, they left the door open for Styles.
"We invite you to see for yourself, and then decide based on facts. We are happy to open our doors, take you behind the scenes, and have our trainers and vets answer any questions you have."
Styles hasn't stated if he's going to take SeaWorld up on their offer or not, but it will definitely be interesting if he does.