Harry wore a t-shirt sporting the Dolphin Project logo at a recent One Direction concert and tweeted earlier this week: "Just had lunch with @LincolnOBarry @RichardOBarry and @CalAurand Check out @Dolphin_Project and see if you support them like I do."
1D boss Simon Cowell recently voiced his support of The Dolphin Project, responding to fans of the Xtra Factor who complained about footage of captive dolphins.
He tweeted: "Reading your tweets. I had no idea Xtra Factor producers filmed with dolphins. This will NOT be showed on Saturday. I think you all know my view on cruelty to animals so thank you all for your concern."
Simon added: "I hope to announce a project in the near future which will bring the issues of dolphins and whales in captivity to a mass audience. It's something we have been working on for a while."