Heath Ledger’s death 16 years ago is still as tragic as the day it hit headlines, and now director Stephen Gaghan has claimed a new heartbreaking detail following his passing. The Dark Knight star died from an accidental overdose ahead of the second instalment of the Batman franchise hit theaters. The Oscar-winning actor was also in the middle of filming another flick when he died, The Imaginarium of Doctor Parnassus. At the time, his part in the movie was re-cast with more actors, including Colin Farrell, Johnny Depp and Jude Law. However, the three celebrities went on to refuse pay checks, i…