The highly-anticipated Harry Potter reunion special on HBO Max, which honors the film franchise's 20th anniversary, saw the superstar trio of Daniel Radcliffe, Emma Watson, and Rupert Grint come together with their fellow co-stars to reminisce on the good times they had on set. While there were a lot of fun and heartwarming moments, there were also a few unexpected revelations given by the cast that managed to catch fans off-guard.