News of Alan Rickman's passing [1] shot through the hearts of Harry Potter [2] fans on Thursday. The cast is in mourning [3], and Daniel Radcliffe penned an exceptionally touching tribute [4] to his late friend. However, if you'll always count yourself as a fan of Snape's, you need to read this letter [5] that Rickman wrote for Empire magazine in 2011, just after he finished his work on the final Harry Potter film. Just be warned: it will make you cry.