Harry Potter star Daniel Radcliffe ordered the movie sequel's cast and crew to pose for photos 20 feet under water - for a bizarre Christmas card The 15-year-old actor - who plays the boy wizard - had finished shooting a mermaid scene for his latest movie Harry Potter And The Goblet Of Fire and decided to take advantage of the specially constructed tank, by staging an aquatic photo shoot and asking computer experts to add reindeer antlers and snow for his festive cards. Radcliffe explains on his website DanRadcliffe.co.uk, "It was taken 20 feet down in a tank specially constructed at Leavesden Studios in Watford, England. Every person you see helped me through this very demanding sequence."