A clip from a documentary featuring the late Heath Ledger's "Joker Diary" resurfaced online and provided clues as to just how far he went to play on his role as The Joker in "The Dark Knight" by Christopher Nolan.

Heath won a 2009 posthumous Oscar award for his role after his tragic death in January 2008 due to accidental drug overdose.

According to Entertainment Weekly, the documentary was from Germany entitled "Too Young to Die: Heath Ledger," and the clip that resurfaced featured Heath's father, Kim.

The documentary was from 2012 and according to Pajiba, it was originally uploaded in 2013, and it resurfaced last year and again this year.

The clip seems to have caught the attention of web browsers when it was posted on Reddit last weekend.

The short clip featured Kim looking at Heath's diary that showed just how much his son had prepared for the role of The Joker.

According to Kim, his son locked himself in a hotel room in London for "a month or so" to internalize his upcoming character.

The father described it to be typical of Heath whenever he is assigned a role in a movie. However, keeping a diary took it to a "whole new level."

In the video, it can be seen that the diary contained pictures of clowns, playing cards, photos of hyenas, scenes from Batman comics, and even photos from "A Clockwork Orange."

The clip also showed an entry labeled "The Hospital Room" and Kim made a comment about how Heath's sister Kate used to dress him up in a nurse outfit and that the actor also wore a nurse outfit in the movie.

The most haunting part of the clip was when Kim arrived at the diary's final page, which showed the words "BYE BYE" scribbled in all caps.

Heath Ledger was just 28 years old when he was found unresponsive in his bedroom in a New York apartment.