Bizarre reason Heath Ledger was constantly licking his lips in The Dark Knight

Heath Ledger's performance as the Joker is unforgettable for many reasons, but film fans particularly adore his character because he managed to expertly put his own sadistic stamp on it.

The late and great actor, 28, is largely considered to be the best person to ever step into the shoes of the Clown Prince of Crime, as he focused on the psychological aspect of the complex character.

Opting for a much less polished look in comparison to his predecessors, the Brokeback Mountain star reimagined the Joker in his own way for The Dark Knight and unknowingly created the blueprint for how to play an antihero flawlessly.

As well as the bedraggled appearance, he decided to sport while portraying the infamous character, Ledger also included some mannerisms which have since become trademarks of the Joker.

Take a look at this:

Batman fans may be thinking that this is where he may have came up with the idea to incorporate an unusual habit with his tongue into his performance, but they would be sadly mistaken - as it was actually a complete fluke.

Viewers will already be well aware that Ledger's version of the Joker was constantly licking his lips, which became something of a signature trait.

But the reason behind how the Australian actor came up with it is pretty interesting to say the least.

According to movie buff Allen Tsai, who regularly shares behind-the-scenes secrets from iconic flicks on TikTok, told how Ledger leaned into the lip-licking as it kept his Joker look intact.

He explained: "Did you know that in The Dark Knight, the reason the Joker constantly licks his lips is actually because of the prosthetic scars on Heath Ledger's face?

"They kept falling off whenever he'd speak, so Heath would lick his lips to keep them in place.

"Eventually he made this tic a part of the Joker's character."

Heath Ledger was constantly licking his lips while playing the Joker (Warner Bros)

According to Entertainment Weekly, this nifty bit of intel comes from the documentary I Am Heath Ledger, which was released in 2017.

In the doc, we hear how the prosthetics used for the Joker's trademark scars kept coming loose, which meant Ledger had to do what he could to keep them on his face while filming.

He even went as far as creating his own 'Joker Diary' while filming The Dark Knight - which he was posthumously awarded an Academy Award for Best Supporting Actor - to jot down his thoughts and ideas.

The iconic actor actually came up with the trait by coincidence (Warner Bros)

It contained notes and inspirations behind his acting choices, revealing a plethora of terrifying muses including hyenas, clowns, comic strips and Alex DeLarge from Stanley Kubrick's cult classic, A Clockwork Orange.

Ledger's dad, Kim, revealed that his son had put himself into a self-imposed exile to really delve into the Joker's chilling psyche and 'locked himself up in a hotel room for weeks' to master the character.