Potterheads are in a tizzy over the world premiere of the final Harry Potter movie, "Harry Potter and the Deathly Hallows, Part 2." Daniel Radcliff and J.K. Rowling took the stage for the live-streaming event amid thousands of adoring fans crunched into London's Trafalgar Square. Rowling summed up her feelings about this celebration as "very, very emotional." The film opens in U.S. theaters on July 15. While fans feel bittersweet about the end of Harry Potter, many are excited about Rowling's new venture, Pottermore, an interactive website with extra Potter material Rowling has reportedly been "hoarding.".